Delivery By Cesarean Section And Risk Of Obesity In Preschool Age Children; Research Review

Today’s guest post is written by Dr. Mark Sloan, pediatrician and author of Birth Day: A Pediatrician Explores the Science, the History and the Wonder of Childbirth.  Dr. Sloan takes a look at the study released in May, 2012 examing the relationship between Cesarean deliveries and obesity in preschoolers. – SM

I don’t recall learning much about childhood obesity in my early-1980s pediatric residency. This was partly due to the fact that obesity wasn’t all that common—only about 7% of kids fell into that category at the time—and partly because the solution seemed obvious, and not quite worthy of medical attention. “Join a baseball team, kid,” my senior resident once told an overweight boy with asthma. “And you,” he said, pointing an accusatory finger at the boy’s mother. “Stop buying cookies, okay?”

Creative Commons photo by LouLou-Nico

One thing I did learn a lot about in residency, though, was cesarean section. The U.S. cesarean rate topped 20% for the first time, up from 6% just a decade earlier.  I spent a steadily increasing amount of time in operating rooms, waiting for an obstetrician to hand me a baby.

We all thought the rise in cesareans was a good thing—think of the lives saved, the brain damage avoided, we told ourselves.  If anyone had suggested cesarean birth might be creating long-term health problems for those “saved” babies, we would have scoffed. And had anyone suggested that it might lead to a lifetime of obesity, we’d have laughed them right out of the hospital.

But here we have it: The cesarean rate is now 50% higher than it was in 1980. (Hamilton BE, Martin JA, & Ventura SJ. 2011)  The rate of childhood obesity has tripled. (Ogden C. & Carroll M., 2010) Is this just a coincidence?

Theories abound as to the cause of the childhood obesity epidemic. It’s all those sodas and sports drinks laden with high fructose corn syrup. Or it’s sugary, fatty, super-sized fast food. Or video games, the loss of Physical Education at school, bad parenting, unsafe neighborhoods, too little sleep, too much schoolwork, or all of the above. Just about any variable you can think of has been scrutinized for obesogenic potential.

And now, thanks to Dr. Susanna Huh and her research team at Harvard University, we can add cesarean section to the list of suspects.

Creative Commons photo

Huh’s team studied 1,255 mother-child pairs recruited between 1999 and 2002 as part of Project Viva, a longitudinal prebirth cohort of mothers and babies in eastern Massachusetts. A trained research assistant conducted in-person visits with the mothers during pregnancy, and with mothers and babies shortly after delivery, and at 6 months and 3 years after birth. At each visit the children’s length, weight and skin-fold thicknesses were assessed.

Their results: Children born by cesarean section were twice as likely to be obese at 3 years of age than those born vaginally. (Huh, SY, Rifas-Shiman, SI, Zera, CA, Edwards, JWR, Oken, E, Weiss, ST, & Gillman, MW, 2012) This relationship held up even after adjusting for factors like the mother’s weight, ethnicity, age, education, and parity, and the baby’s gender, gestational age, and birth weight.

The Huh study wasn’t designed to look at the reasons for the increased risk of obesity associated with cesarean birth, but the Harvard team suggested several possibilities:

  1. The most likely culprit is the known alteration of the gut microbiota—the sum total of all the micro-organisms found in the healthy human bowel—caused by cesarean birth. The microbiota of vaginally-born babies is populated by bacteria acquired from the birth canal and maternal rectum. In cesarean-born babies, who do not traverse the birth canal, the microbiota is dominated by bacteria from the skin and the hospital environment. In general, cesarean-born babies have an abnormal gut microbiota: too many carbohydrate-loving Firmicutes bacteria and too few obesity-preventing Bacteroidetes species, compared with the microbiota found in vaginally-born babies. This same gut microbiota profile is associated with obesity in adults; the link between the two appears to be low-level bowel inflammation triggered by the abnormal microbiota, which alters how food is absorbed  from the gut and processed within the body.
  2. The second possibility is that cesarean birth is just a stand-in for something else that’s happening at the same time. In discussing their findings, Huh and colleagues speculate about antibiotics routinely given to women during the course of a cesarean. Antibiotics given during pregnancy may temporarily alter the newborn gut microbiota, but research results are mixed as to whether this is a significant, lasting effect.
  3.  It’s possible that all of this has nothing to do with the gut microbiota. There are maternal and placental hormones, and immune and inflammatory factors, surging in a mother’s (and baby’s) bloodstream during labor. These, obviously, are missing to some extent if she never completes labor, and are largely absent if a cesarean is performed before labor starts. The lack of a normal maternal stress response to labor could adversely impact the development of the newborn immune system, theoretically leading to the gut inflammation associated with obesity.
  4.  Differences in mode of feeding may be involved as well. The study’s cesarean babies breast-fed for a significantly shorter time than did the vaginally-born babies. Though the authors don’t comment on this, early weaning is also associated with alterations of the infant gut microbiota.

My best guess: the cesarean-obesity link is likely a big mash-up of all of these, plus other factors no one has yet even dreamed of. Further research by Dr. Huh’s team and many others in the coming months and years will hopefully clarify the picture.

In the meantime, the risk of future obesity is one more factor maternity care providers and their pregnant clients should weigh before deciding on how a baby will be born.

Would you be likely to share this connection between mode of delivery and childhood obesity with  your students when teaching about benefits and risks of cesarean section?  Do you think if more families knew about this connection, they might make different choices surrounding the labor and birth of their baby and avoid interventions likely to increase their risk of a cesarean birth.  Is this information just one more thing that blames mothers for things that are out of their control?  Please share your thoughts in our comment section. -SM


Hamilton BE, Martin JA, Ventura SJ. Births: Preliminary data for 2010. National vital statistics reports; vol 60 no 2. Hyattsville, MD: National Center for Health Statistics. 2011.

 Huh, Susanna Y, Rifas-Shiman, Sheryl L, Zera, Chloe A, Edwards, Janet W Rich, Oken, Emily, Weiss, Scott T, & Gillman, Matthew W. (2012). Delivery by caesarean section and risk of obesity in preschool age children: a prospective cohort study. Archives of Disease in Childhood. doi: 10.1136/archdischild-2011-301141

Ogden Cynthia, & Carroll Margaret, U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, Division of Health and Nutrition Examination Surveys (2010). Prevalence of obesity among children and adolescents: United states, trends 1963-1965 through 2007-2008. Retrieved from CDC/National Center for Health Statistics website: http://www.cdc.gov/nchs/data/hestat/obesity_child_07_08/obesity_child_07_08.htm

About Mark Sloan

Mark Sloan has been a pediatrician and a Fellow of the American Academy of Pediatrics for more than 25 years. Dr. Sloan graduated from the University of Notre Dame in 1975, received his medical degree from the University of Illinois, Chicago, in 1979, and completed his pediatric training at the University of Michigan. Since 1982 he has practiced with the Permanente Medical Group in Sacramento and Santa Rosa, California, where he was Chief of Pediatrics from 1997 to 2002. He is an Assistant Clinical Professor in the Department of Community and Family Medicine at the University of California, San Francisco. Dr. Sloan’s first book, Birth Day: A Pediatrician Explores the Science, the History and the Wonder of Childbirth was published in 2009 by Ballantine Books. His writing has appeared in the Chicago Tribune, the San Francisco Chronicle, the San Francisco Examiner, and Notre Dame Magazine, among other publications. Dr. Sloan can be reached through his blog.

Babies, Cesarean Birth, Childbirth Education, Guest Posts, New Research, Research , , , , , , , ,

  1. | #1

    Thanks, Dr. Sloan for this guest post. It is amazing how things are being revealed as having an impact, when we start to change things…cesarean section clearly affects so many things, with more such discoveries on the horizon no doubt. Certainly not things that were thought about…it seemed such a predictable and effective method of birth, but unless medically necessary, really the risks don’t outweigh the benefits. Research must be done on what women can do to mitigate the impact, when a cesarean is necessary. Exposure to vaginal secretions post birth for those cesarean babies? other things?

  2. avatar
    | #2

    The c-section rate should be lowered — but we can also support mothers who birth by c-section to have early bonding in the operating room (skin to skin, breastfeeding, etc.), take probiotics and give it to their infants, long-term breastfeeding, and other other forms of self and babycare. While there needs to be less c-sections, there also needs to be transformations in the way c-sectopms are done.

  3. | #3

    Very interesting post. Thanks!

  4. avatar
    | #4

    C section and formula feeding are not about blaming mothers. Mothers birth how they need to birth, and feed their babies how they need to feed their babies. But…..if there are differences, if the mode of delivery or mode of feeding, or use of antibiotics does cause changes to the ecology of the baby’s gut, and if these changes cause alterations in gene expression, then mothers need to know. Interventions from the norm will always have consequences and pretending otherwise “so mothers don’t feed guilty” is wrong.

  5. avatar
    | #5

    I have been telling moms about the connection between breastfeeding and obesity for the last 10 years. But I agree that it is a complicated web of issues that have yet to be teased apart with regard to mode of delivery. I hope that these issues will be studied further and moms get more of a say in how their babies enter the word! Vbac should be available to everyone, unless medically indicated.

  6. | #6

    My Rapid Response to this study was published online in the BMJ Archives of Disease in Childhood:


    It’s titled “Findings do not inform maternal request caesarean risk” and this is an extract:

    “Hypothetical theories about the potential impact of gut bacteria remain unproven, and women choosing a caesarean are weighing up other perinatal risks such as stillbirth, asphxiation, shoulder dystocia and serious intrapartum injuries, as well as maternal risks including pelvic organ prolapse, incontinence, psychological trauma and unpredictability of care.”

  7. avatar
    | #7

    @Pauline Hull (@PaulineMHull)
    There is nothing hypothetical here about the change to gut bacteria with mode of birth. There is also nothing hypothetical about the findings of the study: the children who were born by c section had a 3 fold increased risk of obesity. What is hypothetical, is the link between the two. There is an element of biological plausibility though. And that is what women have a right to know.

  8. | #8


    With respect, I wrote that hypothetical theories about “the potential IMPACT of gut bacteria” remain unproven – not the fact that there ARE differences.

    Also, my BMJ response does not suggest that women are not told about studies like these, but rather that they are told about them in a specific context. The study did not specifically look at maternal request cesareans at 39+ weeks’ gestation, and as stated, any risk must be weighed alongside all other potential birth mode risks for the infant too.

    So while I agree with you that women have a right to know the risks and benefits of different birth plans, I remain concerned that many natural birth advocates are very keen to ensure women know all about the possible risks of surgery, but their communication about all the possible risks of a planned vaginal birth is not nearly as thorough.

  9. | #9

    @Pauline Hull (@PaulineMHull)

    While the exact cause is unknown, the association between cesarean birth and a number of chronic childhood conditions, such as asthma, eczema, and obesity, is well beyond hypothetical.

    As I noted in my post, the well-documented alteration of the gut microbiota in cesarean-born babies is one of several possible explanations. Supporting this theory, Van Nimwegen, et. al., recently found that babies whose guts are colonized at one month of age by clostridium difficile—a hospital-acquired bacteria more commonly found in cesarean-born babies—are more likely to have wheezing and eczema throughout the first 6-7 years of age. The study showed that clostridium difficile is the mediator of that association. (1)

    And while I agree that Huh’s study does not specifically address maternal request cesareans, the fact that the risk of obesity at age 3 was doubled for all cesareans should give pause to women considering an elective procedure.

    I write from a pediatric perspective. The vast majority of babies do not suffer catastrophic birth outcomes, regardless of mode of delivery. Many millions, though, go on to lead lives impacted by obesity, asthma, and other chronic conditions. Whatever the underlying mechanism, those who are cesarean-born do have a moderately increased risk of these and other disorders.

    Pregnant women have a right to know this, and to add it to the many other factors that go into mode-of-delivery decisions. Providers of maternity care, particularly those inclined to promote elective cesareans or discourage VBACs, should do the same.

    Mark Sloan M.D.
    Santa Rosa, CA

    (1) van Nimwigen F. Mode and place of delivery, gastrointestinal microbiota, and their influence on asthma and atopy. The Journal of Allergy and Clinical Immunology, 128:5, 948-955.e3, November 2011

  10. | #10

    Hi Dr. Sloan – thanks for taking time to present the evidence that babies born by c-section have their risk doubles for obesity …hmm, just makes me wonder, what are we doing in our healthcare system?

  11. | #11

    Studies that have shown increased risks with asthma, eczema, and obesity have contained mixed cesarean data. For example, the asthma link has been shown in studies that included babies born at an earlier gestational age than the recommended 39+ weeks for maternal request. That’s not to say that it will never be proven, but as of right now, the jury is out on the impact of cesarean by choice at the recommended gestational age.

    I think it’s a stretch to suggest that the “many millions” of infants who “go on to lead lives impacted by obesity, asthma, and other chronic conditions” might be substantially due to their mode of birth, as opposed to their subsequent life experience (particularly with the obesity risk), but again, with regards maternal request at 39+ weeks’ EGA, we don’t know for sure.

    What we do know from research however, of the babies who do “suffer catastrophic birth outcomes”, is that the vast majority occur following a planned vaginal birth and not a planned cesarean birth at 39+ weeks EGA. Pregnant women have a right to know this too.

    Add to this the reduced maternal risk for pelvic floor disorders, and all I’m saying is that while it is absolutely the prerogative, and indeed the responsibility, of providers of maternity care to advise women of known cesarean birth risks, women should also be furnished – just as comprehensively – with the known risks of a trial of labor.

  12. | #12

    @Mark Sloan M.D.
    Please see comment no.11 below; thank you.

  13. | #13

    @Pauline Hull (@PaulineMHull) Your perspective, while interesting, seems to be one that gives me pause. Unless there is a medical/health reason (mother or baby or both) determined prenatally or intrapartum or an emotional reason (psychological condition or history) that precludes a vaginal birth, I cannot understand why one would promote a planned elective cesarean over the physiological norm, which is vaginal birth. As the cesarean rate has risen over time, to almost 1 in 3 babies in the USA (I recognize that you are in the UK) some of the potential consequences of this rise are being evaluated and studied. We cannot expect there to be no impact. The value of normal, physiological birth, in the absence of interventions unless necessary, can not be underestimated.

  14. avatar
    | #14

    I can’t even begin to understand the mindset that advocates major abdominal surgery as ‘safer’ than a well-supported physiologically normal process . Perhaps we should start encouraging people to have gastric feeding tubes placed to protect them from the dangers of ingesting food orally- like dental disease, choking, heartburn and indigestion, or burns from too-hot food.

  15. | #15

    @Pauline Hull (@PaulineMHull)

    Some follow-up comments:

    1) The Huh/Harvard study which found the doubled risk of obesity in cesarean babies was well-controlled for a number of maternal and newborn variables, including gestational age.

    2) As for asthma, meta-analyses of dozens of studies have found a moderate increase (overall ~ 20%) in the risk of asthma for cesarean-born children. Many of these studies are controlled for gestational age, among other variables. (1).

    3) I don’t understand how babies born to the subset of women who request a cesarean birth without medical need would somehow be exempt from the risks associated with cesareans in general. Is there evidence or a proposed mechanism to support that theory?

    Mark Sloan

    (1) Isolauri E. Development of healthy gut microbiota early in life.
    Journal of Paediatrics and Child Health
    Volume 48, Issue Supplement s3, pages 1–6, June 2012

  16. | #16

    My head is spinning with all this information. I would like to see all the numbers and data that is used to support these findings. Both if my daughters were born by cesarean. In the 39th hour of a non medicated vaginal birth we had to rush to get an emergency cesarean where they actually lost me for a bit. And that traumatic experience made me elect for a cesearean with my srcond daughter. Both of my children are in the 20th percentile for weight. My 5 year old is 42″ and 32 lbs while my 7 year old is 50″ and 50lbs. They were 7lbs 10oz born and are now skinny minnys with no health problems. So how is having a cesearean making my daughters obese? I still go by the need of getting our children out and moving instead of being tv and video game junkies. Every day I beat myself up about getting an elective cesarean with my second daughter and now getting the blame for a possible weight problem doesn’t help.

  17. | #17

    Emily – I apologize if my post made you feel blamed or guilty about choosing a cesarean. That decision should be made by a woman and her maternity care provider, weighing the pros and cons that are unique to her situation. When I write of the increased risk of chronic health conditions related to cesareans, it’s in the spirit of helping to inform that decision.

    I am not anti-cesarean. I’ve seen the good the operation can do, both professionally and personally. In fact, I owe my son’s life to a timely cesarean. But as a pediatrician I’m concerned about the research in the last decade that suggests that cesareans aren’t as benign for babies as they were once thought to be.

    Having a cesarean doesn’t mean a child is sure to become obese or develop asthma and such, nor does having a vaginal birth mean those things won’t happen. But cesarean birth does appear to make those conditions somewhat more likely to occur. And like any issue involving children’s health, it’s best to minimize risk as much as is reasonably possible. That’s why I think it’s important that women be aware of this research.

  18. | #18

    Here is one example of a study cited in your ‘Isolauri E’ reference above: “The Finnish Birth Cohort study compared asthma rates in children at 7 years of age and found vaginally delivered children had lower rates of asthma compared with those delivered by Caesarean section.”

    My point is that when informing pregnant women, at the PLANNING stage of birth, it is not good enough to compare the outcomes of best case scenario vaginal birth outcomes with cesarean outcomes, and for too long, many comparative studies have done just that.

    You write, “I don’t understand how babies born to the subset of women who request a cesarean birth without medical need would somehow be exempt from the risks associated with cesareans in general. Is there evidence or a proposed mechanism to support that theory?”

    I find this very concerning coming from a medical professional. Absolutely there are different risks with maternal request at 39+ gestational weeks, as stated by the NIH and ACOG for example, and this is precisely what our book is all about.

    The risks of an emergency cesarean or a planned cesarean at earlier gestational ages ARE different. That’s not to say that a maternal request cesarean is risk free – it’s not. I’m also not suggesting that a maternal request cesarean has fewer risks than a spontaneous vaginal birth with no adverse outcomes – it does not. But no woman is guaranteed a safe vaginal birth, even a woman with a low risk pregnancy, so she needs to be informed of the risks of each birth PLAN.

  19. | #19

    What about the psycho social aspects leading to an increase c/s rate and obesity. We live is a society where we are results oriented. Women want a baby without the process of birth, doctors want a surgery/procedure not a labor/process with variables. That attitude is translated to the way families live with fast food and instant gratification vs. activity and whole foods. This does not speak to all c/s there are still the < 10% that are for legitimate medical reason and probably are less likely to result in obese children.
    A woman who can be a health advocate for herself and her baby in pregnancy will probably carry those skills into parenting and provide a well rounded life for her child including healthy foods and lots of activity, less screen time and more experiences. Yet again a reason I would like to advocate for early pregnancy classes so that we have an opportunity to educate women from the beginning of pregnancy and not just in the last trimester when they are less likely to find good providers who believe in the normal process of labor and birth. And look at the labors that are more likely to end in c/s: ones where women are sitting and waiting for birth to happen to them instead of labors that are most likely to result in an vaginal birth ones where women are up, moving and engaged in the labor process, engaged in what is happening to them.
    As I mentioned before there are always the 10% or so of c/s that save lives…I had one of those. I had a c/s for rapidly progressing HELLP. My son is tall and sinewy. I believe the psycho-social is much more to blame for obesity and increasing c/s rates than most medical theory. We need to stop looking a something to blame and take control of our lives and our bodies.
    Pregnancy is such a wonderful time to teach lifelong healthy living women are motivated and engaged. Seize the opportunity to counter the downward spiral.

  1. | #1
  2. | #2

cheap oakleys fake oakleys cheap jerseys cheap nfl jerseys wholesale jerseys wholesale nfl jerseys