EBB 416 - Evidence on Big Babies

0:00Dr. Rebecca Dekker: Before we dive into today's episode, I want to tell you about our latest signature training on RSV, or respiratory syncytial virus. Figuring out which RSV prevention options are available in pregnancy and infancy can be confusing. Your options depend on the time of the year, when RSV season begins, where you live, and how far along someone is in pregnancy. This leaves a lot of expecting families and the birth workers who support them with questions that need answers. So on October 27th, Dr. Sara Aylshire and I from Team EBB spent an hour and a half breaking down the evidence about RSV. We talked about who can get the RSV vaccine in pregnancy and how they qualify, which babies can receive the RSV antibody shot, and the ingredients, benefits, and risks of both options.

0:47Dr. Rebecca Dekker: We also looked at the latest RSV hospitalization rates, covered the exceptions to the various rules about getting the vaccine or the antibody shot, and answered as many of your questions as we could during the live Q &A. If you missed this training, there's still time to get access. You can become an evidence-based birth pro member for just$47, the lowest price we've offered on the monthly membership in years. You'll get the full replay of the RSV training, a continuing education certificate, and 30 days inside the pro membership. And that$47 rate continues for as long as you choose to remain a member.

1:21Dr. Rebecca Dekker: Plus, we're giving pro members special copyright permission to share the RSV lecture handout with clients. So you can hand your most curious clients all of evidence-based births research notes and all the citations they could possibly want. You can join at ebbirth.com slash membership, and we'll put the link in today's show notes as well. And with that, let's jump into today's episode. Hi everyone. On today's podcast, we're going to talk about the evidence on big babies.

1:51Dr. Rebecca Dekker: Welcome to the Evidence-Based Birth Podcast. My name is Rebecca Decker and I'm a nurse with my PhD and the founder of Evidence-Based Birth. Join me each week as we work together to get evidence-based information into the hands of families and professionals around the world. As a reminder, this information is not medical advice. See ebbirth.com slash disclaimer for more details. Hi everyone, and welcome to today's episode of the Evidence-Based Birth Podcast. My name is Dr. Rebecca Decker, pronouns she, her, and I'll be your host for today's episode. Today, along with my co-host, Dr. Sara Aylshire, we are excited to bring some brand new evidence-based information to you all about the evidence on induction or cesarean for suspected big babies.

2:39Dr. Rebecca Dekker: So I'm joined today by Sara, who is a member of the EBB research team, and she has come onto the podcast a number of times to share research updates. And today, Dr. Sara Aylshire is here to talk about our latest signature article update, all about the research evidence on the suspected big baby label that is commonly put on people during pregnancy and to describe the health conditions and the interventions like labor inductions and cesareans that are commonly associated with big babies. So, Sara, welcome back as co-host. Hi, Rebecca. Thank you for having me back on. We've been working on a few projects related to big babies over the past year, so I'm really excited to talk about everything we've added to the article, including a brand new large study on big babies.

3:29Dr. Rebecca Dekker: Yeah, and I just want to remind everyone, whenever we do a signature article update, if you want to access any of the materials, the full-length texts, the scientific references, and all the hyperlinks to those references that go with today's episode. It's really easy. We've made it easy to remember. Just go to evbirth.com slash bigbaby or evidencebasedbirth.com slash bigbaby, and everything is waiting there for you. And just as kind of a flashback, I originally published the research evidence on big babies in 2012. It was a quote, big problem back then. And you would think that maybe sharing the evidence publicly would help and maybe it has, but the topic of big babies is still out there.

4:18Dr. Rebecca Dekker: It's still causing ruffles or ripples in the birth community. And I myself talk to people all the time who are being told that they are having a suspected big baby. So it's really important that we update the research on this article and SARA has been working really hard on this all year. As a content note, in today's episode, we will be talking about complications that may occur during childbirth, including childbirth injuries, stillbirth, newborn death, and newborn brain damage. With that being said, a baby's weight is important for a lot of reasons, right? It's one of the first pieces of information that parents share after their baby is born.

4:58Dr. Rebecca Dekker: and one of the first things that people ask, like how much did your baby weigh? And when parents are telling stories about their new babies, they tend to talk about their size. Maybe they were so small that they had to go out and buy new clothing or maybe the baby was so big that they had to return the newborn size diapers and start with the size ones. So the average baby born at full term weighs around seven pounds, five ounces. And if a baby's born much larger than average, Starting at around 8 pounds, 13 ounces, they're considered a quote unquote big baby. And if it's thought before the birth that the baby might be bigger than average, then they're considered a suspected big baby.

5:43Dr. Rebecca Dekker: And this information may be conveyed along with the recommendation that you should have an induction or a cesarean because your baby is getting too big. So the purpose of the signature article is to share the evidence on what is the accuracy of the suspected big baby label and what are the health conditions and interventions that are commonly associated with big babies. And we hope that this episode is helpful for you if you're pregnant or if you're hoping to become pregnant and you just want to learn more about what to expect if your provider suspects you have a big baby or maybe like our podcast producer, Cece, you were a big baby yourself and you're listening because you want to learn some of the research evidence that goes along with all the stories that people told about how big you were when you were born.

6:29Dr. Rebecca Dekker: Or we have a lot of doulas, childbirth educators who listen to the podcast and their clients have questions about induction or cesarean for a suspected big baby, especially if they had hoped to go into labor on their own. I know we also have a lot of nurses, midwives, physicians who listen and they may feel conflicted about this label of big baby. So hopefully we can help all of you out by covering the evidence on what is a big baby, how common they really are, what are some of the factors linked with having a big baby, what is the type of care that might be offered if a provider thinks you're having a big baby.

7:06Dr. Rebecca Dekker: And we're also going to go through five questions that can help guide an evidence-based approach to the suspected big baby situation. So we're going to cover the answers to these questions. Number one, do big babies have a higher chance of their shoulders getting stuck, also known as shoulder dystocia? Number two, are big babies at higher risk for other childbirth problems? Number three, can we accurately tell in advance if a baby is going to be born big? Number four, does an induction keep a baby from getting bigger or lower the risk of cesarean? And number five, what are the benefits and risks of planning an elective cesarean for a suspected big baby?

7:48Dr. Rebecca Dekker: And of course, we will close out by talking about the bottom line. So, Sarah, you did a lot of the heavy lifting on the research on this article. Could you start off by defining what a big baby actually is and how common they are? Sure. So some researchers consider a baby to be big when they weigh around 4 ,000 grams or eight pounds, 13 ounces or more at birth. And others will say that the baby is large if they weigh 4 ,500 grams or nine pounds, 15 ounces or more at birth. Babies are considered to be extremely large if they're born weighing more than 5 ,000 grams or a little bit over 11 pounds.

8:32A baby can also be called large for gestational age if their weight is greater than the 90th percentile at birth. So in other words, a large for gestational age baby is when a baby is born way more than 90 % of all other babies born at that same gestational age. So if you're in the top 10 percentile of 38 weekers, you would be a large for gestational age baby, even if you might not meet some of those other cutoffs. The medical term for a big baby is macrosomia, which literally means big body. A baby cannot be diagnosed with macrosomia until after it's born, when the baby is weighed for the first time.

9:17About one in 10 babies in the United States are born big. As we were working on this article, we looked at all of the data for babies born in the United States between 2016 and 2024, just to see what the current numbers were. So during this time in the United States, 8.78 % of all babies born at 39 weeks or later weighed between 8 pounds 13 ounces and 9 pounds 15 ounces. And only 1.17 % were born weighing 9 pounds 15 ounces or more. Something else that I found interesting as we were working on this update is that the rate of big babies has actually decreased over time. In a study of all recorded births in the United States between 1971 and 2017, which was over 147 million babies, researchers found that the rate of macrosomia decreased from 8.84 % to 8.07%.

10:12The authors noted that improved treatments for people who have gestational diabetes and improvements in fetal monitoring might have been a reason for this decrease in macrosomia.

10:24Dr. Rebecca Dekker: So it sounds like only about 1 in 10 kind of meet the cutoff for a big baby. And then 1 in 100 to be like a bigger baby. Yeah. And the very biggest babies of all. So Rebecca, do you have any big baby stories? Um, I mean, I was curious. It's always interesting to think about like what you weighed. And then if you had children yourself, what they weighed, I think I was around eight pounds, six ounces, and I was very long, but my mom is very short, not quite five foot tall. So for, I guess for her, she felt like I was a big baby. And my first weighed only six pounds, eight ounces that I gave birth to, but then my second and third babies both weighed exactly nine pounds, two ounces.

11:07Dr. Rebecca Dekker: So they did meet the big baby cutoff for both of them. And both of their births were actually easier than my first. And I think it had to do with fetal positioning, which we won't really get into in this article. But I think when you combine optimal fetal positioning, it might help lessen some of the effects of having a big baby, but we don't really have a lot of research on that. So what about you? Yeah. I think it was also eight pounds, six ounces. Funny enough, I should say that. And I remember when I was pregnant with our daughter, I was thinking that she must be around like seven or eight pounds.

11:43Cause I think my husband was about three and a half kilos when he was born and I was eight pounds and she was really small. She was just barely over the six pound mark. So I was suspecting, you know, a, at least like a moderately big baby getting close to that cutoff. And I actually had a pretty small child.

12:03Dr. Rebecca Dekker: yeah yeah I was surprised when my first was small or at least small for what I expected because I expected a bigger baby and my husband's tall and I just figured it would be you know at least in the eight pound range but funny enough she had a huge growth spurt in the next couple weeks and she was born a little early at 39 weeks so I think maybe if she had stayed in the womb she would have been the same size as my others I'm not sure yeah yeah and we were talking earlier in the episode about, you know, you have a baby that's smaller than you're expecting. That was my story. I had to go out and get a lot more like really, I mean, I think we actually ended up getting like one preemie outfit and a bunch more newborn clothes.

12:43Cause I was totally unprepared. I thought zero to three months would be fine. And my baby was just drowning. Yeah. And then my second and third

12:50Dr. Rebecca Dekker: kids couldn't fit in their newborn size clothing. So all of that went to waste, you know, it had to be given to someone else. So they went straight into three month size clothing. And so baby numbers, like the weight of your baby is fun to talk about, but it also has, you know, some implications for your birth. So we'll get into that later. Yeah, absolutely. Rebecca, would you mind walking us through what factors are linked with potentially having a big baby? Yeah. So as we mentioned, you know, we know big babies tend to run in families. So that's why often people talk about, like I was born at this weight and my partner was born at this weight.

13:25Dr. Rebecca Dekker: So we might expect our baby to be in that range. And the length of your baby and their size can be influenced by genetics and family history. There's also evidence that it's more common to have a big baby if the baby's sex is male. And if you have diabetes before pregnancy, like type one or type two, or if you develop diabetes during pregnancy or gestational diabetes, there might be higher rates of big babies compared to those who are not diabetic. However, with gestational diabetes, researchers have found that if you manage your gestational diabetes through diet, exercise, or medication if needed, that it brings your chances of having a big baby down to the typical levels that we talked about at the beginning of this episode.

14:09Dr. Rebecca Dekker: In addition, there's high quality evidence from a review of 15 randomized trials showing that if you exercise during pregnancy, whether or not you have diabetes, there's a significant decrease in the chance of having a big baby compared to those who do not exercise at all during pregnancy. There are a few other factors that researchers have shown to be linked with the chances of giving birth to a big baby. This could include your body mass index before pregnancy if it's higher than average, gaining a higher weight gain than recommended during pregnancy, getting pregnant at 35 or older, going post-term, going past 42 weeks and zero days, a prior history of having a big baby.

14:53Dr. Rebecca Dekker: So you tend to repeat sometimes that experience. And then there's some rare genetic conditions or syndromes that can be associated with big babies. So Sarah, we've talked about what is a big baby. And before we move on, I have to share with you a funny story, interlude, intermission between talking about the research. So sorry, you sent me, you know, a draft of our signature article and I was reading it. And as I do, sometimes I will sit there and just stare at a section over and over. And at one point I was saying to myself, there's a literally a subtitle that says, what is a big baby? And I was thinking about what is a big baby?

15:33Dr. Rebecca Dekker: What is a big baby? And I was thinking out loud, of course. And I know what a big baby is, but I was trying to think like, how do I explain this to someone? What is a big baby? What is a big baby? And all of a sudden, from the other corner of the room, Dan, my husband goes, someone who whines and complains a lot. And I thought that was like one of the worst dad jokes I'd ever heard. But also, how did I never think of that? I've been talking about big babies since 2012, and that joke never popped into my head. And so I shared it with the team. And wouldn't you know it, his birthday was a few weeks later.

16:09And if you're watching on YouTube, you can see the team actually made him a shirt

16:12Dr. Rebecca Dekker: in EBB branding that says, what is a big baby in huge font? Someone who whines and complains a lot. So that's just our little interlude for, for humor purposes. I hope, I hope you all find that entertaining. We're here talking about the science of big babies and Dan is over there joking about it. So, so Sarah, when you're suspecting that you have a big baby and it's not somebody who whines and complains a lot, but a large baby, an actual suspected big baby, what might your provider's recommendations be if they think that this might be an issue? Sure. So at the end of pregnancy during the third trimester, your provider will be monitoring your baby's growth.

16:59They can do this by measuring the fundal height or the distance from the top of the uterus, also called the fundus, and the pubic bone. And they can do this with their hands, and they'll be assessing to see if the baby is either maybe too small or getting too big, just making sure that the baby is sort of growing the way they would expect it to be growing based on the rest of your pregnancy. If your pregnancy is deemed high risk, your provider may also perform a third trimester ultrasound to check on the baby's growth and development, and some providers actually just do a routine third trimester ultrasound for a growth check as a matter of course.

17:37Either way, during the third trimester, providers may begin to voice concerns if they think your baby is growing to be too big. Some of the best evidence that we have about typical care for suspected big babies in the United States comes from the Listening to Mothers survey series. This is a series of research on sort of trends and what's happening in maternity health care in the United States. It comes out every few years. And the most recent survey in the series was actually just published this year in 2026 by Sakala et al. And they found that while roughly one in 10 babies will be born large, about one in four people who participated in the Listening for Mothers study reported that their provider told them that their baby would be large or that their providers suspected that they were having a big baby.

18:28Dr. Rebecca Dekker: That's pretty high, like a one in four chance of being told your baby's too big. So what actually happened then? Were all of these suspected big babies big? The short answer is actually no. Of this group, of this 25 % who were told they were going to have potentially a big baby, 74 % of those people had babies born in the typical or normal weight range. So between 5.5 pounds to 8 pounds, 13 ounces. And actually 4 % of this group who were suspected of having a big baby ended up having a baby that's considered small. So their babies were born weighing 5.5 pounds or less. Only 22 % of those people who were suspected or predicted to be having a big baby ended up actually having a large baby.

19:18And of those, only 6 % had a baby who weighed more than 9 pounds, 15 ounces. So among those who were not told that their babies would be large, that those other three and four, 84 % of that group had babies born in the normal weight range. 12 % had babies who were born small and 4 % had babies who were born weighing more than 8 pounds 13 ounces. So what we also learned from this study is what happens when your provider thinks that the baby might be big. The researchers found that the suspicion of a big baby could also impact how people gave birth. Of the 25 percent of the survey respondents whose providers predicted that they would have a big baby, 40 percent reported that their provider recommended they have a labor induction due to the expected size of the baby.

20:11And 28 % of those reported that their provider recommended they have a cesarean because their baby was expected to be large. So we know from this research that if a baby appears large or is suspected to be big, a care provider will usually either recommend an induction or an elective cesarean because of concerns about the baby's potential weight. Whether or not this approach is evidence-based depends on the answers to five major questions. And these are the questions that Rebecca asked at the top of the episode. Do big babies have a higher chance of their shoulders getting stuck, also known as shoulder dystocia?

20:48Are big babies at higher risk for other birth problems? Can we accurately tell if a baby is going to be big? Are those predictions accurate? Does induction keep the baby from getting any bigger or does it lower the risk of cesarean? and what are the benefits and risks of an elective cesarean for a suspected big baby. So Rebecca, do you want to tackle that first question about shoulder dystocia in big babies? Yeah. So one of the main concerns providers have with a suspected big baby is that they

21:20Dr. Rebecca Dekker: might experience a complication called shoulder dystocia. Shoulder dystocia occurs during a vaginal birth when the baby's head has been born, but one or both shoulders are stuck in the pelvis. So shoulder dystocia means that the care provider is going to have to take extra physical actions or maneuvers to help get the baby out. Sometimes you'll hear OBs or midwives refer to shoulder dystocia as a quote unquote obstetric nightmare. And I think it's because there is a long history of fear related to the situation. If you attend births in any capacity, you might know that if someone says shoulder during the second stage of a birth when the baby's actually coming out.

22:04Dr. Rebecca Dekker: Now everyone in the room springs into action to try and help get the baby unstuck. So while it's important to take shoulder dystocia seriously, it's also important to know that shoulder dystocia by itself is not considered a bad outcome. It's only a bad health outcome if an injury or death occurs as a result of the shoulder dystocia. But the fear with the shoulder dystocia is that the baby being stuck could result in a bad outcome. That could happen if there's a long delay between the birth of the head and the rest of the baby. It's possible that during that delay, the baby may experience low oxygen, which could lead to brain damage.

22:44Dr. Rebecca Dekker: In rare cases, the baby's collarbone or clavicle could be broken during birth by accident, or a provider might have to break it rarely on purpose to get the baby out in an emergency, there's also a rare risk that a baby could experience a temporary or permanent nerve injury that could impact their ability to use their shoulder, arm, or hand. So shoulder dystocia occurs in anywhere from 0.2 % to 3 % of all vaginal births of babies who are in a headfirst position. However, the chance of experiencing shoulder dystocia does increase with the birth weight of the baby. So if your baby weighs less than eight pounds, 13 ounces, or less than 4 ,000 grams, the chances of shoulder dystocia are about 1 % or one in a hundred.

23:36Dr. Rebecca Dekker: If the baby weighs between eight pounds, 13 ounces and nine pounds, 15 ounces, which is between 4 ,000 and 4 ,499 grams, the chance of shoulder dystocia is about 5 % to 9%. If your baby weighs 9 pounds 15 ounces or more or 4 ,500 grams or more, the chance of shoulder dystocia goes up quite a bit to between 14 % and 23%. These chances of shoulder dystocia can also be impacted by diabetes. Diabetes significantly increases the chance of shoulder dystocia due to the impact of maternal blood sugars on a baby's size and how their weight is distributed on their body. Interestingly, people with high blood sugar levels during pregnancy have higher chances of shoulder dystocia during birth, even if their baby is not considered to be big.

24:28Dr. Rebecca Dekker: This is because of that difference in weight distribution. It's possible that the baby's head might be relatively small compared to the size of its shoulders and abdomen, which could make birth of the shoulders more difficult. Now, although big babies are at higher risk for experiencing shoulder dystocia, at least half of all cases of shoulder dystocia happen in smaller or normal-sized babies. That's because overall, we have many, many more normal-sized babies being born than big babies. So even though their chance on its own is smaller, we have more of those babies. So that's one reason why researchers think it's important for shoulder dystocia to always be prepared for so that the teen always knows what to do because it doesn't just happen at big baby births.

25:16Dr. Rebecca Dekker: In terms of the risk of death, death from shoulder dystocia is possible, but it's very rare. In 1996, researchers looked at all the studies that had been done up to that point that reported the rate of death due to shoulder dystocia. They had 15 studies looking at 1 ,100 cases of shoulder dystocia and zero deaths. In two other studies, the rates of infant death were 1 % and 2.5%. And in a study published by Hoffman et al. in 2011, researchers looked at more than 132 ,000 births to singleton babies born in headfirst position. About 1.5 % of the babies in the study had a shoulder dystocia, so there were roughly 2 ,000 cases.

26:04Dr. Rebecca Dekker: And of those, about 100 newborns experienced injuries. Most of those injuries were what we'll call brachial plexus injury, and I'll talk more about that in a little bit, or collarbone fractures. Out of the 101 injured infants, there were zero deaths and six cases of brain damage due to lack of oxygen. With the six brain-damaged infants, the average delay between the birth of the head and the birth of the shoulders was 11 minutes, which is very long. Another study in 2021 published by Mendez Figueroa looked at 130 ,000 singleton births of living babies who were born after 34 weeks in the United States between a six-year period.

26:47Dr. Rebecca Dekker: And they found that shoulder dystocia happened in 1.7 % of births. They had 2 ,159 cases of shoulder dystocia. Out of these, there were five cases of something called newborn asphyxiation when the baby does not get enough oxygen before, during, or immediately after birth, and one case of brain damage related to the lack of oxygen. So because of everything I've talked about, at least half of all shoulder dystocia cases happen in babies that are not big. And we're going to talk about this in a little bit, but we can't predict with certainty who's going to have a shoulder dystocia. It's always a possibility in any birth.

27:28Dr. Rebecca Dekker: And you cannot eliminate the risk of some of these injuries with cesarean, which we'll talk about later. So it's important for healthcare providers to just always be up to date on their training and like doing regular drills as a team for the possibility of treating a shoulder dystocia. It is something that can be managed in the birth room, but training and practicing your skills is important. Absolutely. It sounds like that's sort of the difference between shoulder dystocia being something that happens during a birth versus shoulder dystocia causing serious problems. It's like the training and the expertise of people to resolve it quickly and safely.

28:07So as we were talking, you mentioned that sometimes a stuck shoulder can result in nerve damage. Did you want to talk a little bit about this condition too?

28:15Dr. Rebecca Dekker: So, you know, as we were just saying, most cases of shoulder dystocia can be safely managed by the care team during the birth to get the baby out in a timely manner. But in some cases, including in some cases where perhaps providers were not managing the shoulder dystocia correctly, you can experience a nerve injury called brachial plexus injury. So brachial plexus injury is sometimes called brachial plexus palsy. It can lead to weakness or paralysis of the arm, shoulder, and or hand on the side that you experience this injury. This happens in about 0.9 to 1.5 out of every 1 ,000 vaginal births in the United States.

28:56Dr. Rebecca Dekker: And although it's often associated with shoulder dystocia, a baby does not have to have a stuck shoulder during the birth in order to experience a brachial plexus injury. In fact, about half of brachial plexus injury cases happen without shoulder dystocia. And there's a little bit of a mystery as to why that occurs. In one study that looked at 387 children who had experienced a brachial plexus injury, 92 % were born vaginally and 8 % were born by cesarean. Researchers have documented that brachial plexus injury happens in about three per 10 ,000 cesarean births. So although rare, it can happen without that experience of going through the pelvis and having your shoulders being stuck.

29:39Dr. Rebecca Dekker: So most of the time a brachial plexus injury is temporary. But some infants who have this injury, about 10 % to 18 % will end up with a permanent injury, which is defined as arm or shoulder weakness or paralysis that persists for more than a year after birth. It's estimated that there are anywhere from 35 ,000 to 63 ,000 people living with permanent brachial plexus injuries in the United States. And this condition does require ongoing physical therapy for an infant and child. It can be a big diagnosis that parents and children have to contend with. So if you go to our signature article, we kind of get deeper into this topic, a brachial plexus injury.

30:26Dr. Rebecca Dekker: We also share a link to a story of someone who experienced one so you can kind of see what that looks like in real life. Also, we have an important table in the article that I really encourage you to go look at. it's table number three and this is where we break down the rates of shoulder dystocia and brachial plexus palsy and the rate of permanent disability looking at the different weight categories so you can see how it changes if the baby is more typical size if it's a big baby but not the biggest babies and then we also look at the bigger babies and kind of look at how those percentages change.

31:04Dr. Rebecca Dekker: But I do want to, again, reassure people that research has shown that when healthcare workers do annual, so yearly interprofessional trainings to drill on how they should use evidence-based techniques to manage shoulder dystocia, they can lower. And in some cases, some hospitals have found they've been able to eliminate cases of brachial plexus injury with the shoulder dystocia. So I always think it's a great advocacy tip to know, like, do they practice handling this at your hospital or with your healthcare team? So that kind of answers that first question. Does the risk of stuck shoulders go up with the big baby?

31:47Dr. Rebecca Dekker: And I think the research shows that it does. So Sar, do you want to answer the second question? Are big babies at higher risk for other birth problems other than shoulder dystocia? Sure. So in general, the risk of health problems with a big baby increases as the baby's size increases. So the bigger the baby, the more potential complications at birth that they're exposed to in terms of risk. Some of the risks associated with having a big baby include an increased chance of having a cesarean, a potential increase in perineal tears. So this can be a tear of the tissue either in the vagina, extending through the perineum down and sometimes in the most extreme cases into the rectum, postpartum hemorrhage, newborn complications like the baby needing some help with their blood sugar after birth or needing supportive care in a neonatal intensive care unit, and stillbirth.

32:44Yeah.

32:44Dr. Rebecca Dekker: And I'd like to encourage our listeners to go to the full signature article where we give the actual numbers for each of these increased risks. For example, the perineal tears, the severe tears that you were mentioning, which are sometimes known as third or fourth degree tears, the risk might go up, for example, from a 0.9 % with a baby who is not big to 1.7 % with a big baby. So it's not like guaranteed that you're going to have one of these severe tears, but the risk does go up compared to babies that are not big. And we have other studies that go into detail about that. and the other complications that you mentioned.

33:20I also wanted to briefly add on to the info about

33:25Dr. Rebecca Dekker: stillbirth because I think that's one reason why some doctors recommend cesareans for suspected big baby or planned early inductions because they believe there's this higher risk of stillbirth. We have several very large studies on this topic. And I just want to say that in general, researchers have found that actually the smallest babies have the highest risk of stillbirth, While large babies tend to have lower or average risks of stillbirth, it's only the very biggest babies that tend to have a slightly higher than average risk of stillbirth. And those would be the babies weighing 5 ,000 grams or more or roughly 11 pounds or more.

34:03Dr. Rebecca Dekker: And that's thought to be due partially to the higher rates of maternal diabetes in babies that are born weighing that size. So does that help, Sarah? Yeah, absolutely. Absolutely, you know, at the extreme ends where either a baby is very big or very, very small. It's not just like an innate characteristic of that baby, but maybe an indication there's something else going on that could be impacting them. And the thing that might be making them very small or very big could also be affecting their health in other ways. And although big babies are at a higher risk for some problems, a care provider's suspicion that a baby will be big also carries its own set of risks.

34:41The research shows that this perception, regardless of if it's true or false, changes the types of recommendations that care providers will make and can influence birth outcomes, increases the likelihood of a cesarean, regardless of the actual size of the baby.

34:57Dr. Rebecca Dekker: so yeah and i'll interrupt there yeah and i think it's really interesting that you know in this signature article update we now have a total of 10 different studies over several decades showing that it's often the suspicion of a big baby not the baby size itself that can influence outcomes so leading to higher induction rates higher cesarean rates and higher diagnoses of labeling a labor as stalled, even if the baby is not actually big. So there's some really interesting research methods where they will break it down and look at people who actually gave birth to big babies and those who did not have big babies, but they were all told they were having big babies.

35:40Dr. Rebecca Dekker: And then they look at the outcomes. And then we also have people who are pregnant with big babies, but nobody suspected it. And they actually tend to have much better outcomes than the suspected big baby situation. So we have some pop-out boxes on the signature article online where you can kind of go look at, I think we have like four or five different sample studies where you can learn about how that bias, it's almost like when the provider has a bias in that fear that you have a big baby, it changes how they behave and then it changes the outcomes of your birth. Also changes how they talk to you about your ability to give birth, right?

36:16Yeah, absolutely. That suspicion can really just sort of like change a person's experience at the end of their pregnancy.

36:22Dr. Rebecca Dekker: Yeah. I mean, I've had people tell me recently about, you know, being told that they have a big baby and then the next time actually your baby's size is fine. And then the next time, oh, your baby's getting too big. And this kind of like definitely affects your mental state when you're towards the end of pregnancy and how you think about your ability to give birth. And then also your provider not believing in you too, like suspecting that, oh, this baby's going to be big. we're worried. Let's start talking about ways we can intervene. And that can also negatively impact a birth. Absolutely. So yeah, like you were saying, Rebecca, we go into a lot of detail in the signature article.

36:59And if you would like to know more about any of these risk factors, I definitely recommend checking that out. And as we've been talking, we've been talking about how the suspicion of a big baby can impact care and what a big effect that can have on people's experiences, their birth outcomes, but how effective are we at actually predicting a baby's size before they're born?

37:21Dr. Rebecca Dekker: So evidence shows that both ultrasounds and physical exams where the healthcare provider puts their hands on you are not particularly great at being able to accurately determine if a baby will be big at birth. And I think that's why we hear so many varying stories, right? You'll hear the story, oh, my provider said my baby was big and they were huge, like they were born enormous. Or my provider said my baby was big and they ended up being small or my baby was totally normal after they told me it would be big. So we have all these like different anecdotes. So it can be helpful to look at the research.

37:59Dr. Rebecca Dekker: And we know that after a baby is born, measuring their weight is as easy as placing them on that scale where they don't like it. They're like crying, like, give me back to my parent. However, trying to figure out how much a baby weighs when it's inside your abdomen, inside your uterus, and you can only feel it from the outside through a lot of layers with hands, or if you're using ultrasound to take measurements, this presents a different challenge. It's not as easy as putting a baby on a scale. So the ultrasound fetal weight measurements are relying on like measuring different body parts with ultrasound and then using mathematical formulas to make an educated guess on how much the fetus weighs.

38:43Dr. Rebecca Dekker: So a number of factors can impact the accuracy of the estimate they give you, including how experienced is the ultrasound technician? Is the technician making any errors? Is it difficult to make any of the measurements? How is the baby positioned in your uterus? What's your body size? If just one of the measurements that they take is inaccurate, then that inaccuracy can be multiplied several times when it's entered into a mathematical formula used to estimate your baby's weight. So time and time again, researchers have found it's very difficult to predict a baby's size accurately before it's born.

39:22Dr. Rebecca Dekker: In fact, two studies have found that a pregnant woman's own estimate that her baby weighed more than 4 ,000 grams, it was a big baby, is just as accurate as a healthcare provider who's trying to measure from the outside of your belly. There was this classic study done in 2005 where researchers combined all of the studies that had ever been done on ultrasound and estimating a baby's weight at the end of pregnancy. So at that time, there were 14 studies looking at the ability of ultrasound to predict a baby weighing more than 8 pounds, 13 ounces. The studies range, the accuracy of ultrasound ranged from 15 % to 79%, with most studies showing that the accuracy was less than 50%.

40:05Dr. Rebecca Dekker: So this means that for every 10 babies that an ultrasound technician predicts will weigh more than 8 pounds, 13 ounces, 5 weigh more than that, and the other 5 will weigh less. Ultrasound is even less accurate at predicting babies who are going to be born even bigger. So for those weighing nine pounds, 15 ounces or greater at birth, there were three studies on that weight range and they found that the accuracy of ultrasounds ranged from 22 % to 37%. This means that if you're given a prediction for 10 babies that they're all going to weigh more than nine pounds, 15 ounces at birth, only about two to four of those babies will actually weigh this amount at birth and the other six to eight babies will weigh less.

40:50Dr. Rebecca Dekker: They've also looked at the accuracy of ultrasound in predicting big babies with diabetes, and they have found that the accuracy is a bit higher with diabetes, possibly because if you're diabetic, you're more likely to have a big baby. So it's easier to predict a big baby mathematically if you know someone is more likely to have one to begin with. We've also found a few studies looking at the accuracy of MRI, comparing that to ultrasound. and in general, MRI does outperform ultrasound. However, if you've ever had an MRI, you know, the machines are enormous. They're incredibly expensive to operate.

41:30Dr. Rebecca Dekker: There's also long waiting lists in a lot of places. They're typically reserved for people who have more urgent needs. So although this might be more accurate than an ultrasound, the expense and the long wait times kind of make it impractical just to use to figure out if you have a big baby or not. And there was another systematic review published in 2013 that concluded, quote, there is no clear consensus with regard to the prenatal identification, prediction, and management of macrosomia, end quote. So these authors explained that the main problem with big babies is that it's very difficult to accurately diagnose them before birth.

42:10Dr. Rebecca Dekker: it's really only a label that can be applied after the birth when you put the baby on the scale and measure their weight. So, Sarah, that's just some of what we cover in the article about the accuracy of fetal weight estimates using ultrasound, MRI, and measuring with your hands from the outside of the belly. We also go into detail on what's the plus or minus. If they predict a baby weighs this weight, how far above or below could your baby actually weigh? so check out the article if you want to learn more so that kind of answers that third question the answer to the third question is no it's really not easy to identify a big baby before it's born so the next question has to do with induction like does induction keep a baby from being bigger does it prevent shoulder dystocia does it lower the risk of cesarean can you talk about the evidence on that yeah so in this section i'll be tackling that question of like does induction keep the baby from getting any bigger or does it lower the risk of cesarean?

43:11And there's, generally speaking, conflicting evidence about whether or not induction for a suspected big baby can improve health outcomes. And in our censor article, we cover a few different studies, but for our podcast today, I'll just be talking about two of those studies. One is the 2025 big baby trial done in the United Kingdom. And the second is a 2023 Cochran Review, where researchers looked at multiple randomized trials together. So the Big Baby trial by Gardosi et al., published in 2025, is the largest randomized controlled trial to test whether early labor induction for a suspected big baby can prevent shoulder dystocia.

43:54There were two main purposes of the study. One, to determine whether early induction of labor is associated with a lower risk of shoulder dystocia compared to standard care, and two, to investigate if waiting to induce until 38 weeks instead of 37 weeks for shoulder dystocia would still reduce the risk. The researchers recruited women who had a suspected big baby with an estimated fetal weight greater than what they called the 90th customized percentile, meaning that their babies were larger than 90 % of all other babies at the same gestational age, between 35 and 38 weeks gestation from 106 hospitals across the United Kingdom between 2018 and 2022.

44:39People who were excluded from taking part in this trial were those who had type 1 or type 2 diabetes or gestational diabetes, those who already had a scheduled induction or a scheduled cesarean, people who were pregnant with twins or multiple babies, and people whose babies were not in a head-down position. The researchers estimated that an earlier birth would reduce the risk of shoulder dystocia by about 50%. So they estimated that in order to see statistically significant results, meaning that their results could apply to the general population, that they weren't just sort of an accident based on who was in the study, that they would need 4 ,000 participants at least.

45:18Recruitment was actually stopped early on by the advice of the Data Monitoring Committee, who was overseeing the study, because they determined that they would actually need more than 12 ,000 participants to see significant results. This is because Shoulders' TOSHA was so uncommon in this study. The researchers had been recruiting participants for nearly four years, and it would have taken an incredibly long time to recruit such a huge number of participants. And at the time that the study was stopped, their recruitment rate was only 10 people per week. Ultimately, the researchers enrolled 2 ,893 participants.

45:55The participants were randomly assigned to one of two groups. The induction of labor group between 38 weeks, zero days, and 38 weeks, four days of pregnancy, and there is about 1 ,400 participants in that group, and the standard care group. And standard care was defined as a hospital's usual care. In a standard care group, to create enough of a difference in gestational age between the groups, induction before 39 weeks, four days was discouraged unless there was a medical reason. And that group also had about 1 ,400 participants.

46:28Dr. Rebecca Dekker: The researchers also used two different statistical methods to analyze their results. And this will become important later when we're talking about the results and what the researchers concluded from them. Intention to treat was the first approach they used. This keeps everybody in their original assigned group, including those who do not end up following their group protocol. Intention to treat is a preferred method of statistical analysis for most trials because it's more representative of what actually happens and is less prone to bias. It's also the gold standard for reporting data from randomized trials.

47:06They also use PER protocol. So PER protocol only analyzes those people who adhere to the protocol for their assigned group. PER protocol is more prone to bias, but it can also give a better sense of how effective a treatment is under perfect conditions where people are adhering totally and perfectly to the protocol for their group. Data analysis with PER protocol is rarely done when researchers publish their results from randomized trials. So in Gardosi et al's intention to treat analysis, the incidence of shoulder dystocia was 2.3 % in the induction group and 3.1 % in the standard care group.

47:46This difference was not statistically significant, meaning that any difference between the two groups was most likely due to chance. However, perhaps because the intention to treat analysis did not give statistically significant results, the researchers also published a per-protocol analysis with 77.9 % of the total participants in the study. The rate of shoulder dystocia in the per-protocol induction group was 2.3 % versus 3.7 % for the per - protocol standard care group. Removing participants who did not adhere to the study protocol made this a statistically significant difference and allowed the researchers to describe their trial as showing a decrease in shoulder dystocia with early labor induction.

48:35Participants in the induction group were more likely to have longer hospital stays, 3.4 days versus three days with the standard care group, and they were more likely to have a second-degree tear, 28 % versus 24.5 % in the standard care group. Participants in the induction group were less likely to have an elective cesarean, 2.7 % versus 4.2 % in the standard care group. They were less likely to have an emergency cesarean, 25.7 % versus 28.8 % in the standard care group, and they were less likely to have an instrumental birth, 16.3 % versus 17.9 % in the standard care group, and less likely to have an episiotomy, 19.8 % versus 22.6 % in the standard care group.

49:26There were no significant differences between groups and other maternal health outcomes, including the rate of third or fourth degree tears or adverse maternal outcomes or complications that occurred before being released from the hospital. There were also no significant differences between the induction group and the standard care group in newborn health outcomes, including admission to the NICU, the rate of birth injury, or complications associated with being born too early. In the study, two infant deaths occurred. One baby died in the induction group as a result of sepsis or a blood infection that occurred after prolonged induction.

50:11One baby died in the standard care group from complications associated with a shoulder dystocia. So what are the takeaways with the big baby trial? Early induction prior to 39 weeks for a suspected big baby might reduce the incidence of shoulder dystocia, but this result was only found when researchers changed their method of data analysis. Researchers also found that inductions do not need to take place at 37 weeks of gestation to see a benefit and suggest that providers can wait until 38 weeks to induce for a suspected big baby to potentially see a benefit. In their discussion, the researchers recommended a policy of shared decision making that includes information about the potential benefits to a 38-week induction as well as limitations when it comes to estimating fetal weight by ultrasound.

51:03In addition, any shared decision-making conversation that includes data from the big baby trial should also disclose that researchers had to stop their study early because shoulder dystocia was so uncommon and they found no difference in NICU admission or birth injury rates.

51:19Dr. Rebecca Dekker: Yeah, I think this study is a really interesting exercise in evaluating a study closely, which if you want even more details, we do that in the full signature article. Also, the shoulder dystocia, even all of these babies were suspected big babies, right? The overall rate of shoulder dystocia was two to 3%. So 97 to 98 % did not have shoulder dystocia, which I think is encouraging for those of you who have a suspected big baby label. Yeah, absolutely. You know, I think it's also a good insight into just how difficult it can be to do these large trials. You know, things happen that impact recruitment.

51:54Researchers want to do the best science that they can, but under real world conditions, it can be really hard.

52:00Dr. Rebecca Dekker: I mean, yeah, I think people have no idea how hard it would be to recruit 4 ,000, let alone 12 ,000 people into this study. So they definitely, it looks like they did the best they could. And this is the data we have. And it's probably the largest study on big babies and inductions that we'll ever get would be my guess. Yeah, absolutely. Another study we'll look at is this 2023 Cochran review. And in this review or this meta-analysis, researchers combined four studies in which 1 ,190 non-diabetic pregnant people with suspected big babies were randomly assigned either to an induction between 37 and 40 weeks or to wait for spontaneous labor.

52:42Dr. Rebecca Dekker: When researchers compared the induction group to the waiting group, they found a decrease in the rate of shoulder dystocia in the induction group, about 41 cases per 1 ,000 births in the elective induction group, down from 68 cases per 1 ,000 in the waiting group. They also found a decrease in birth fractures in the elective induction group, 4 per 1 ,000 versus 20 per 1 ,000 in the waiting group. To prevent one fracture, it would be necessary to electively induce labor in 60 people. The researchers found an increase in the treatment of newborn jaundice, 11 % versus 7 % in the induction group. On average, babies weighed 178 grams, or six ounces, less when labor was electively induced early compared to those who were assigned to wait for labor to take place on its own.

53:36There were no differences between groups and rates of cesarean, vacuum or forceps-assisted births, NICU admission, brachial plexus injury, or low APGAR scores. Three of these four studies reported death rates, and there were zero deaths in either group. The researchers in these studies did not look at a patient's satisfaction with their care or any long-term health outcomes for either the birthing person or the baby.

54:04Dr. Rebecca Dekker: So sorry, you've shared information from the big baby trial and then the Cochrane Review, which did not include the big baby trial, what is kind of your summary of what they've found about induction for suspected big babies? Yeah. So an induction for a suspected big baby might help reduce the risk of certain complications like a shoulder dystocia or a birth fracture. And it might help babies be smaller at birth, which makes sense that in utero growth that might've happened in the body is now going to take place outside because a baby's been born. But the induction would have to have been done pretty early at around 38 weeks for this to have an effect.

54:42And we don't have strong evidence on whether or not this induction would reduce the rate of a cesarean. It doesn't seem to lower the risk of health complications from shoulder dystocia like NICU admission. And of course, we would still have the same problem that we do not have a precise way of determining during pregnancy at least, which babies are definitely going to be big. So a big chunk of the time, you're going to be inducing early for a suspected big baby who might not actually be born big at all. Rebecca, do you want to talk a little bit about the benefits and risks of deciding to have an elective induction for a suspected big baby?

55:19Dr. Rebecca Dekker: Yes, that's kind of our final question, right? We've been working our way from numbers one through five, and I think the answers to one and two about shoulder dissociation health complications was yes. The answer to number three about, can we predict a big baby with no? And the answer to number four, does induction improve outcomes is kind of like mixed, right? It's not. Yeah. Sometimes, sometimes not. Yeah. So, so what are the benefits and risks of elective cesarean for a big baby? You know, we've talked a lot about induction and we see a lot of care providers recommending induction for a suspected big baby, but others will skip this step and go straight to recommending a planned cesarean or an elective cesarean.

55:59Dr. Rebecca Dekker: However, researchers have estimated that this type of approach is extremely expensive. It would take thousands of unnecessary cesareans to prevent one case of permanent brachial plexus injury. And in 1996, I know this was years ago, but bear with me. This was a really important analysis. This just goes to show you how long this has been debated amongst clinicians and researchers. But the Journal of the American Medical Association published an analysis proposing that a policy of elective cesareans for all suspected big babies was not only not cost-effective, but that it would have more potential harms than potential benefits.

56:40Dr. Rebecca Dekker: And so the researchers had to calculate, you know, what are the different methods we could use to or approaches for a suspected big baby. So you can have a policy where there's no routine ultrasounds to estimate baby sizes at the end of pregnancies, or you could have a policy where you did routine ultrasounds and then you did elective cesareans for all babies estimated to weigh eight pounds, 13 ounces or more. So for example, my second and third babies would have been planned cesareans, or you would do routine ultrasounds and elective cesareans only for babies who are estimated to weigh 9 pounds 15 ounces or more so kind of reserving that option for the biggest babies.

57:22Dr. Rebecca Dekker: The researchers also looked at results separately for diabetic and non-diabetic pregnant people. Unfortunately most research at this time point was not distinguishing between type 1 and type 2 diabetes and gestational diabetes so the term diabetic could refer to any of those conditions. They found that among those who are not diabetic A policy of elective induction for all suspected big babies over 8 pounds 13 ounces means that really a large number of people and babies would experience unnecessary surgical births. There would need to be 2 ,345 unnecessary cesareans to prevent one permanent case of brachial plexus injury.

58:03Dr. Rebecca Dekker: Back then, that would have cost about$5 million per injury prevented. and then if you adjust for inflation today that means it would cost about 11 million dollars per injury prevented. With the policy of elective cesareans only for those suspected big babies weighing over 9 pounds 15 ounces even more people would have to have unnecessary surgeries mainly because ultrasounds are even less accurate at the higher suspected birth weight ranges. So in order to prevent one permanent brachial plexus injury in babies suspected to be over 9 pounds 15 ounces, 3 ,695 people would need to have unnecessary cesareans at a cost of about in dollars in the 1990s,$8.7 million per injury prevented.

58:53Dr. Rebecca Dekker: But adjusting for inflation today, this would cost about$19.4 million per injury prevented. The researchers also wrote about how policies encouraging elective cesareans for suspected big babies could also increase rates of known risks of cesarean that are higher with cesarean than vaginal birth, including serious infections after the surgery, blood clot disorders, postpartum hemorrhage requiring blood transfusions, and newborn breathing problems. Now, when they looked only at people with diabetes, the results were slightly different. Remember we've said earlier that ultrasound prediction tends to be more accurate of a big baby with diabetes.

59:35Dr. Rebecca Dekker: Also, shoulder dystocia is more common in this group as well, regardless of the baby's size. So they estimated that if pregnant people with diabetes were offered an elective cesarean for every baby suspected of weighing more than eight pounds, 13 ounces, it would only take 489 unnecessary surgeries to prevent one case of permanent nerve damage, that would cost about$2 million in today's money per injury prevented. If people with diabetes only had elective cesareans when their babies were suspected of being 9 pounds, 15 ounces or greater, it would take 443 unnecessary surgeries to prevent one permanent birth injury at a cost of, in today's dollars,$1.9 million per injury prevented.

1:00:21Now, whenever

1:00:21Dr. Rebecca Dekker: you're doing these analyses, they're only as good as the numbers that they plug into their mathematical formulas. So did they, you know, have good numbers for how frequently does shoulder dystocia occur? How accurate are ultrasounds? How many permanent injuries occur with shoulder dystocia in a vaginal birth? And they actually did like a super high quality literature review to get these factors and these numbers to plug into their analysis. You know, one main drawback of the study is that it's now 30 years old. And since then, there have been two newer analyses published, but both of these papers were of really poor quality.

1:01:03Like one of them just assumed ultrasound was accurate

1:01:06Dr. Rebecca Dekker: and the other had a really poor quality review and they used numbers that overestimated the accuracy of ultrasounds. They're kind of like assuming that ultrasound is great. And because both of those research papers, those newer ones did not do a good job of making their assumptions and calculating the analyses, we can't trust the result of those papers. So we don't include their results in the signature article. In summary, so far, evidence does not support planning or suggesting an elective cesarean for all suspected big babies, especially among those people without diabetes. we obviously have no randomized controlled trials on this topic because I think people would not be willing to be randomly assigned to a cesarean birth or a vaginal birth for a suspected big baby and there really are no high quality research studies to see what is happening when doctors are recommending cesarean for big babies in mass scale in real life like if you think about it And listening to mothers, one out of four people were told their baby was too big.

1:02:12Dr. Rebecca Dekker: If all 25 % of those, that sample had cesarean, like what would the results look like? We don't know because nobody's studying it. So I think it's interesting because it seems like, especially when you don't have diabetes, that if you're diagnosed or you're suspected to have a big baby and your provider is presenting a cesarean as a completely safe or safer option than a vaginal birth for a suspected big baby. That's not really an accurate shared decision-making conversation because yes, giving birth vaginally to a suspected big baby does have risks, but also cesarean surgery can carries risks and it may have risks that may affect future pregnancies that you may have.

1:03:00Dr. Rebecca Dekker: So it's important to have full and accurate information about the potential benefits and risks of both options in order to have a true informed decision making conversation. And in our signature article, we link to more resources kind of about the list of harms and benefits of cesarean and vaginal birth. Yeah, we've really only scratched the surface here. There's so much more that we cover in the article. We really expanded it, I think, from its last iteration. I'm really excited to share this version of the article because I know our readers, our listeners, our professional members, especially are always interested in studies that they can look up and that they can read for themselves.

1:03:41And every study that we cite is linked at the bottom. So if you want to go and read the research for yourself, I definitely encourage you to do that. So we're kind of at the end. Rebecca, what's the bottom line on big babies?

1:03:55Dr. Rebecca Dekker: Well, first of all, before I read the bottom line, I want to encourage people to go download the one page handout on the evidence on suspected big babies. It is freely available at evidence-basedbirth.com slash big baby. There's a button right at the top where you can download it. I think that handout will come in really helpful if you're being told you have a big baby. And like I said, this is still in this year of 2026 happening all the time. So, you know, have that information. know it as you're going into your third trimester, take the handout with you to an appointment and talk with your provider about it if needed.

1:04:32You can also ask them, we have this info in the

1:04:35Dr. Rebecca Dekker: signature article. We didn't mention it. We have all the guidelines from all the professional organizations, right? And you can ask them like, what are the guidelines say about this? Oh, well, and then they'll have to actually share the evidence with you. But in summary, from EBB's perspective, I think you can break down the bottom line between those without diabetes and those with some type of diabetes. So when there's no diabetes, I think the summary is that although big babies can be associated with some health problems, we do not have an accurate way of identifying big babies in advance. If a care provider predicts a big baby based on ultrasound or physical exam, they will be right half the time and wrong half the time.

1:05:19Dr. Rebecca Dekker: Ultrasound weight results at the end of pregnancy can fall anywhere from 15 % above or 15 % below the baby's actual weight. About 7 to 15 % of big babies have shoulder dystocia or difficulty with the birth of their shoulders. Although we saw in the big baby trial that suspected big babies that rate was even lower, it was about 2%. The chance of a permanent nerve injury due to shoulder dystocia is about one out of every 555 babies who weigh between 8 pounds 13 ounces and 9 pounds 15 ounces and one out of every 175 babies who weighs 9 pounds 15 ounces or greater. It's really important for healthcare providers to regularly train in their skills in managing shoulder dystocia as this can happen in any birth and a skilled healthcare team can prevent injuries.

1:06:14Dr. Rebecca Dekker: Researchers have also consistently shown that if a care provider thinks that you're going to have a big baby, not only may their guess be inaccurate most of the time, but the suspicion of a big baby by itself can lead to worse birth outcomes. This is thought to be because the fear of a big baby leads many care providers to manage labor in a way that increases the risk of cesarean and other complications. Specifically, there's an increase in cesareans for labor arrest or stalled labor when the care provider suspects a big baby, even if the baby's actual weight is not big after all. So if a care provider thinks you're going to have a big baby, it's especially important that you know that they're following the standard definitions of slow labor progress.

1:07:00Dr. Rebecca Dekker: Some people may call that labor dystocia or failure to Progress. We have a whole different signature article on that. It's available at evidence-based birth.com slash failure to progress. And although a policy of early induction at 37 to 38 weeks could prevent some shoulder dystocia cases from occurring, this does not necessarily translate into better health outcomes for the baby. Researchers have not been able to show that early induction decreases the risk of brachial plexus injury or admission to the NICU, and early induction may carry other risks to the birthing parent or baby such as needing treatment for jaundice.

1:07:39Dr. Rebecca Dekker: Older research suggests that a policy of elective cesareans for big babies likely does more harm than good and it would take nearly 3 ,700 elective cesareans to prevent one permanent case of brachial plexus injury in babies who are suspected of weighing 9 pounds 15 ounces or greater. For those with diabetes or gestational diabetes the bottom line is slightly different. That's because ultrasounds in this scenario are slightly more accurate at predicting a big baby, partly because this population has a higher chance of having a big baby to begin with. However, we do know that with gestational diabetes in particular, proper management of blood sugars with diet, exercise, or medication lowers the chance of having a big baby and lowers the chance of shoulder dystocia down to typical levels.

1:08:26Dr. Rebecca Dekker: And we write more about that in our signature article on gestational diabetes located at evidencebasedbirth.com slash diagnosing GDM. And then just like for people without diabetes, it's important if you have some type of diabetes for your care providers to follow the standard definitions of slow labor progress, whether a labor was induced or started on its own, and to learn about the evidence on induction of labor specifically for gestational diabetes, we have a signature article on that available at evidencebasedbirth.com slash inducing GDM. And we'll have all these links in the show notes. There's no strong research data on health outcomes for planning a cesarean with type 1 or type 2 diabetes or gestational diabetes.

1:09:14Dr. Rebecca Dekker: Based on expert opinion only, the American College of Obstetricians and Gynecologists states that there may be some benefit to planned cesareans and diabetics with the suspected big baby estimated to weigh over 4 ,500 grams. Elective cesareans may be more cost-effective with type 1 or type 2 diabetes than they would be in those without diabetes. So that concludes our research update all about the evidence on big babies. I know this is a topic that affects a lot of people around the world. And so I want to encourage you all to go check out the full signature article available at evidencebasedbirth.com slash big baby.

1:09:52Dr. Rebecca Dekker: You can get your one page handout in PDF format, the full length article with all the references hyperlinked and an updated resource guide of other links to check out. So Sarah, I wanted to personally thank you for all your hard work on this article. It has been the fall of big babies for us here at EBV and I'm glad this information is out in the world. Me too. It's been a really interesting article to work on. I've learned a lot and it's been a pleasure. Thank you, Rebecca. Today's podcast was brought to you by the signature articles at evidence-based birth. Did you know that we have more than 20 peer reviewed articles summarizing the evidence on childbirth topics available for free at evidence-based birth.com.

1:10:35Dr. Rebecca Dekker: It takes six to nine months on average for our research team to write an article from start to finish. And we then make those articles freely available to the public on our blog. Check out our topics ranging from advanced maternal age to circumcision, due dates, big babies, pitocin, vitamin K, and more. Our mission is to get research evidence on childbirth into the hands of families and communities around the world. Just go to evidencebasedbirth.com, click on blog, and click on the filter to look at just the EBV signature articles.