Tag Archives: Childbirth

Mode of delivery and childhood illness: A randomized trial in 2004.

03c62f38ce31d41b01e1b5a4031bf11aOne of the biggest difficulties in proving a causal link between cesarean birth and chronic health problems in childhood is the type of research studies that can practically and ethically be done during pregnancy.

The gold standard in medical research is the randomized controlled trial (RCT). In an RCT researchers randomly place subjects into either “treatment” or “control” groups, then expose the treatment group to something—a new vaccine for Infection X, for example—and then compare outcomes in the two groups later on. (In this example, how many kids in the treatment [vaccinated] group came down with Infection X versus how many in the unvaccinated control group?) If there’s a significant difference in outcomes between the two groups, you’ve got a strong argument that the treatment made the difference.

How a randomized controlled trial works. (Credit: SUNY Downstate Medical Center)

How a randomized controlled trial works.**

As you can imagine, randomly assigning pregnant women to cesarean (treatment) or vaginal birth (control) groups is nigh onto impossible—ergo, you can’t do an RCT. This means that virtually all research studies on the issue of cesareans and chronic childhood have been observational in nature—looking backward in time at databases, for example, or trying to fish significant trends out of hospital registries, birth cohorts and the like. The best an observational study can tell you is that A and B are associated with one another, but that’s it—you can’t prove that A actually causes B. An observational study can’t prove that cesareans are a cause of asthma; it can only say that cesareans are associated with an increased risk of childhood asthma.*

So mode-of-delivery RCTs are out of the question…or are they? Actually, in 2004, a Canadian research team did one.

Well done, Northern Neighbors!

Well done, Northern Neighbors!

The multi-center, multi-nation Term Breech Trial wasn’t about whether cesareans might increase the risk of childhood asthma, diabetes and such. It was about trying to figure out whether elective cesarean section or vaginal birth was the safest way to deliver a breech baby at term. Since the existing research was somewhat murky at the time, it was considered ethical (with informed consent) to randomize women to have either a planned cesarean or attempt a vaginal birth.

The particulars of the breech birth debate are best left for another post, but tucked away in the study’s results section was this little nugget:

“…more parents in the planned cesarean birth group than the planned vaginal birth group reported that their children had had medical problems in the past several months…relative risk, 1.41; 95% CI, 1.05-1.89; P=0.2.”

Plain English version (mine): The toddlers who had been in the planned cesarean group were about 40% more likely to have been sick in the previous few months than those in the planned vaginal birth group. The types of medical problems—typical 2 year-old stuff like colds, ear infections and stomach flu—were no different between the groups. The only difference was in the numbers of children who’d gotten sick.

As is the case with all medical research, you can find things in the study to complain about: relatively small numbers, for example, the use of parental questionnaires and the fact that some mothers in planned vaginal birth group ended up having cesareans (and vice-versa), etc.

But here’s my bottom line:

In a randomized trial of pretty well-matched subjects, those babies whose mothers were in the planned cesarean group tended to get sick more often than those in the planned vaginal birth group.

This doesn’t address the issue of chronic illnesses like asthma, type 1 diabetes and the like, but it does support the theory that cesarean birth can mess with a baby’s developing immune system.

* * *

*Here’s an exaggerated example of the trouble with mistaking association for causation: Virtually all adults who die suddenly of heart attacks drank water in the 24 hours before they died. So, drinking water is associated (time-wise) with heart attacks. But you would be wayyyy wrong to say that, based on that association, a glass of water can cause a heart attack.

**Credit: SUNY Downstate Medical Center

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Filed under Asthma, Canada, Cesareans, Immune system, Maternal-child health, Newborns, Vaginal birth

Epidurals: Do they prevent postpartum depression?

Leonardo da Vinci

Leonardo da Vinci

Do epidurals prevent postpartum depression? That’s the intriguing conclusion some people are drawing from a study published in this month’s issue of Anesthesia and Analgesia. But is that conclusion correct?

In a study of 214 women at Peking First University Hospital in Beijing, researchers found that 14% of women who received epidural analgesia during labor reported symptoms of postpartum depression (PPD) six weeks later, compared with 34.6% of women who refused epidurals. The authors point out that their findings don’t necessarily prove that epidurals can prevent PPD, but the language in the discussion sure sounds like that’s what they believe.

But…the premise of this study is flawed from the start, because the investigators compared epidural analgesia to, well, nothing:

“Each parturient made a decision by herself to have epidural labor analgesia or no pain relief at all. Other forms of analgesia are not available at our hospital.”

What does “no pain relief at all” mean at Peking First University Hospital?  Were spouses/doulas/other support people allowed in the room? Did the mothers labor alone? Does “no pain relief at all” mean no freedom to move about, no bath/massage/music/visualization exercises/birth balls, none of the myriad other comfort measures that can reduce pain during labor? It obviously means no nitrous oxide, and I presume no tylenol or ibuprofen, either. In this particular hospital it seems, the choice is pretty stark: you get an epidural or you tough it out.

Which means we’re left with a study of unaddressed labor pain and postpartum depression, not the benefits of epidurals.

Karl Gauss, inventor of Twilight Sleep

Not exactly “new news”: Dr. Karl Gauss, inventor of Twilight Sleep

It’s hardly news that uncontrolled pain can lead to postpartum depression. One of the main drivers in the “painless childbirth” movement of the mid-19th century and the development of Twilight Sleep in the early 20th century was the prevention of neurasthenia—a debilitating combination of anxiety and depression that haunted many postpartum women.* 

This study would be more compelling if the authors had compared epidurals with other pain relief modalities in the setting of a well-supported labor. Otherwise we’re left with the conclusion that uncontrolled labor pain can make women miserable, and medically obliterated pain makes them less so. 

I can’t think of any other form of human pain that would be studied in such an all-or-none way.

* * *

* Department of Shameless Self-Promotion: You can read more about the history of painless childbirth, as well as what a lousy labor coach I was, in my book, Birth Day: A Pediatrician Explores the Science, the History, and the Wonders of Childbirth.  

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Is it the cesarean, or the absence of labor?

Stem cells, pondering the future

Stem cells, pondering the future

I’ve written a fair amount about the association between cesarean birth and the increased risk of immune-related diseases like asthma, diabetes, celiac disease, and even obesity. Most of the research out there has focused on the newborn gut microbiota—the collection of bacteria that colonize a baby’s intestines at birth and play a key role in the development of the immune system. These bacteria are primarily acquired from the mother’s birth canal and rectum during a vaginal birth, but for cesarean-born babies those “pioneer” bacteria are often derived from the hospital environment. Such “wrong” bacteria in the bowel early on can lead to inflammation and, the theories go, to immune-related diseases later in life.

But is the cesarean per se at the root of all this? Or might the absence of labor (or an incomplete labor) have something to do with it? Childbirth is, after all, a fabulously complicated dance of maternal and fetal hormones, anti-oxidants, and other chemicals that are known to influence the immune system. What happens to the newborn’s immune system development when that dance is cut short, or never starts in the first place?

A study from Sweden’s Karolinska Institutet published in the current issue of the American Journal of Obstetrics and Gynecology has me wondering about the “absent-labor” scenario again. The study’s authors compared cord blood samples from babies born by elective cesarean section (ECS) with those who were vaginally born (VB). They looked specifically at hematopoietic stem cells—the precursor cells that go on to become, among other things, the white blood cells that play a critical role in the human immune system.

Here’s what they found: the DNA in stem cells from ECS babies was significantly different from that of the VB babies, particularly in an area devoted to production of antibodies. The study’s genetic analysis is way above my pay grade, but boiled down to the essentials, the differences are all about epigenetics, which is defined as:

 “…the study of changes in gene function that are mitotically and/or meiotically heritable and that do not entail a change in DNA sequence.”

Ouch!

Plain English version (mine): Epigenetics is the study of how genes are turned on and off, typically by the addition of methyl groups (ouch, again!) to genes. The timing of all this light-switch-like activity, and the potential for permanent change, has big-time implications for health throughout life.

The Swedish researchers found that stem cell DNA methylation (the addition of methyl groups to genes) increased steadily with the duration of labor. So one could conclude, couldn’t one, that normal labor plays an important role in preparing future white blood cells for their task, and, ergo, the absence of labor is why everyone’s so chubby these days? Sure, one could conclude that…but one would be jumping the gun, big time.

Hold that smokin' gun, pardner!

Hold that smokin’ gun, pardner!

Why? Because this was a small, observational study—the kind of study designed to make readers sit up and take notice (Hmm…that’s interesting!”) but that requires much more research before any guns start smoking. The small numbers of subjects in this study makes it easier for error to creep in, for example, and there were significant differences between the mothers as well—the ECS group was significantly older than the VB group, and their babies were born an average of a week and a half earlier, factors which might cause their own epigenetic effects.

It’s going to take much larger studies to see if these findings are in fact true, and if so to tease out how significant such cesarean-related epigenetic changes may be in the grand scheme of childhood immune system diseases. A lot of vaginally born kids end up asthma, after all. Including me.

But still, how fascinating! I’m looking forward to reading more about this.

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Photos courtesy Joseph Elsbernd, Jim Sher

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Filed under Asthma, Cesareans, Gut microbiota, Natural childbirth, Obesity

“Birth Day” is out in paperback!

Better than Hemingway

Better than Hemingway

And now, time for some shameless self-promotion…

At long last, Birth Day is out in paperback! What a great gift for you, your partner, your pregnant friends, your non-pregnant friends, your friends with ten kids, your friends who swear they’ll never have kids…basically, Birth Day is a great gift for anyone who has ever been born. (Am I forgetting anybody?)

Birth Day is available from Amazon and other online booksellers, or you can get a signed-by-me copy by ordering directly from my website. It’ll set you back $12.99 plus shipping, but hey, it’s a darned good book:

From the Washington Post:

“Sloan is a graceful writer, and his narrative, like the works of Jerome Groopman, flows easily between memoir, anecdotal reporting and hard science. Birth Day has a natural audience in curious, new and expectant parents. But anyone interested in the complex and, yes, miraculous way we all make it into this world will find lots to wonder over and ponder here, too.”

Aw, shucks…

Okay, commercial’s over! Back to blogging.

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The Brazilian preference?

4753658072_3816f74c0d_nWhat happens when a woman emigrates to a foreign country and then gives birth? Is her birth experience more likely to conform to the country she comes from, or the one she moves to?

For example, is an immigrant woman more likely to have a cesarean birth than a native-born woman, or less? How big a role do the cultural norms and expectations she brings with her from her home country play in determining mode of delivery?

Studies of immigrant birth experiences have been mixed to date. Immigrants do tend to have higher cesarean rates than natives, but interpretations of such findings are often complicated by things like language barriers and the difficulties new arrivals may have in accessing timely maternity care. Teasing out the effects of culture can be tricky.

A Portuguese article just published in the journal PLOS ONE helps to clarify this issue. The study compares cesarean rates between native-born and immigrant Brazilian women in northern Portugal. Two major potential confounders are quickly dealt with: the two groups of women both spoke Portuguese, which eliminates language barrier as a source of cesarean-inducing miscommunication, and all the women were drawn from five public hospitals, so that the care they received was more or less uniform.

The authors found that Brazilian immigrant women had a 50% higher cesarean rate than did native-born Portuguese women (48.4% vs. 32.1%), a difference that persisted even after controlling for such things as demographic, medical and obstetric risk factors. In fact, the cesarean rate for Brazilian immigrants was nearly identical to the overall cesarean rate in Brazil itself.

What explains the native-immigrant difference? The authors speculate it has much to do with attitudes about childbirth that the women brought with them from Brazil:

“This extremely high prevalence [of cesarean birth] seems to be a cultural consequence of attitudes towards labor and the perception of obstetric care among Brazilian women. The majority of Brazilian women perceive cesarean as the most adequate mode of delivery and as a symbol of high social status.”

In other words, culture strongly influences mode of delivery, even far from home. A woman raised to see cesarean birth as a desirable norm is much more likely to end up having one.

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Birth centers: Safe, economical, and great places for low-risk births

2852282606_22551640c8An American woman with a low-risk pregnancy who chooses a midwifery-led birth center for her maternity care is four times less likely to have a cesarean than if she chooses a hospital birth, according to a review published today in the Journal of Midwifery & Women’s Health.

The review highlights the findings of the National Birth Center Study II (NBCSII), which followed 15,574 women who planned and were eligible for birth center births at onset of labor.

Among the NBCSII’s findings:

  • 84% of women who planned and were eligible for a birth center birth at onset of labor were successful in having one.
  • Only 6% of women intending a birth center birth ultimately required a cesarean section, compared with nearly 24% of comparably low-risk women receiving care in hospitals.
  • Emergency transfers from birth center to hospital were uncommon.
  • Fetal and newborn deaths were rare, and comparable to those in low-risk births in hospital settings.
  • There were no maternal deaths.
  • Birth center care is economical and in keeping with the fiscal goals of the Patient Protection and Affordable Care Act (aka “Obamacare”).

Some nuts and bolts of the NBCSII, FAQ-style:

What, exactly, is a “birth center”?

  • The American Association of Birth Centers defines a birth center as “a homelike facility existing within the health care system with a program of care designed in the wellness model of pregnancy and birth.” The key here is “within the health care system”—the integration between birth center and hospital is critical to the success of any birth center. When emergencies arise, a smooth transfer is vital to keeping mother and baby safe.

Who runs these birth centers?

  • The birth centers in the study were all midwifery-led. 80% were staffed by certified nurse midwives (CNMs), 14% by certified professional midwives (CPMs) or licensed midwives (LMs), and the remaining 6% by teams of CNMs,  CPMs, and LMs. (The different types of midwives in the U.S. can be a bit confusing for the layperson—the American College of Nurse-Midwives provides a handy comparison chart.)

What is a “low-risk” pregnancy? Who qualifies for a birth center birth?

  • Here are the AABC’s eligibility requirements for birth center birth: a single fetus in head-down position, with no medical or obstetrical risk factors that might interfere with normal vaginal birth or require interventions like continuous fetal monitoring or labor induction.
  • By those standards, approximately 85% of pregnancies are “low-risk.”

Why did 16% of the women who planned a birth center birth end up giving birth in hospitals anyway?

  • Of that 16%, about one-fourth were transferred to hospitals before being admitted to the birth center, due to medical issues. Of the rest, the majority were for non-emergency problems, such as prolonged labor. Only 0.9% of the birth center women required an emergency transfer during labor.

Is birth center birth really as safe as hospital birth?

  • Yes, according to the NBCSII’s findings. The rates of fetal death (4.7/10,000 women admitted to a birth center in labor) and neonatal death (4/10,000) in the study were comparable to those in other studies in the U.S. and elsewhere, including those of low-risk birth in hospitals. There were no maternal deaths.

Does birth center care really save money?

  • Yes. In this study alone, cost savings–mainly from fewer medical interventions (including cesareans)–were estimated at more than $30 million, and these 15,574 pregnancies represent less than 1% of all U.S. births. Given that expenses for hospital birth in 2008 exceeded $97 billion nationwide, the opportunity for savings in these health-care-dollar-scarce times is enormous.

A few quibbles:

  • The women in the study were mainly white (77.4%), well-educated (71.8% had at least some college education, and 51.8% were college graduates), and married (80.1%). They were also relatively slender (only 5.7% were overweight or obese, compared with more than 50% of all pregnant American women), mentally healthy (3.3% were being treated for depression or other psychiatric disease), and largely free of substance use (1.5% smokers, 0.5% users of other substances). Though the study’s findings on safety and cost-savings compare favorably with other studies of low-risk pregnancy outcomes, it isn’t clear that these findings can be extrapolated to the U.S. population as a whole.
  • Death rates are crude tools for measuring safety, particularly in low-risk pregnancies. I’d like to know more about morbidity–were the birth center babies more, less, or just as likely as hospital-born babies to suffer birth trauma, for example? I suspect they were less likely to have such complications, given the tendency of birth center staff to perform fewer interventions, but I can’t be certain from this study. Hopefully that will be addressed in a future review.
  • What about breastfeeding? Were the birth center mothers more likely to breast feed than those who gave birth in hospitals? Again, I suspect so, and hope that information on breastfeeding will appear in future reviews of NBCSII data.
  • The 79 birth centers that participated in the study represent only 32% of American birth centers. All 79 are AABC members and as such support the AABC’s Standards for Birth Centers. Other, non-member birth centers may or may not adhere to such standards, and their safety records may or may not be as good as those in this study. With new birth centers appearing at a remarkable pace (up 27% since 2010), ensuring high quality care in all birth center settings may be challenging.

Conclusion:

Withe the publication of this review, the well-entrenched belief that hospitals are the safest place to have a baby takes yet another beating. It’s increasingly clear that most women with low-risk pregnancies can safely give birth at midwifery-led birth centers. A personal/professional note: I’ve taken care of a number of families who’ve had their babies at the Women’s Health and Birth Center here in Santa Rosa, California, run by Rosanne Gephart, CNM. (Rosannne and I go way back). They speak glowingly of their experience at the Birth Center.

One caveat, though. Not all birth centers are alike, and it behooves expectant parents to check out things like staff credentials and birth center accreditation, and to ask pointed questions about how the center handles emergencies and hospital transfers, and how often these occur. Membership in the American Association of Birth Centers is a plus, too. Whether choosing an auto repair shop, a law firm, a pediatrician, or a birth center, it definitely pays to do your homework.

Photo credit: JER_0079

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Brazilian women fight cesarean trends

Going natural in Rio?

More than half of all Brazilian children are born by cesarean section, making Brazil one of the most “sectioned” countries in the world. If you’re a woman lucky enough to have health insurance there, the chance of a surgical birth jumps even higher: 82%. In some private hospitals the rates are well into the 90s. Vaginal birth is about as rare as quadruplets in some areas.

A small anti-cesarean movement had begun in Brazil in recent years, but a tipping point was reached recently when a medical regulating agency in Rio de Janeiro banned doctors from performing home births, and–in a move that’s pretty hard to justify–banned doulas from accompanying women to hospitals.

That did it. Women–some marching bare-breasted, others with painted pregnant bellies–took to the streets as demonstrations against hyper-medicalized birth broke out in dozens of cities across the country.

That seems to have gotten the doctors’ attention:

“We need to have a serious discussion in this country to see what can be done to change this culture,” said Olimpio Moraes Filho, one of the head doctors with the Brazilian Association of Obstetricians and Gynecologists. “Women are starting to rebel, and they should.”

Ok, fine…time to discuss a problem that’s been out of hand for a few decades. But how did it get this way in the first place?

There are many threads to the issue, and all of them led to one common path: a medical culture that has turned normally progressing births into unnecessarily stressful, painful ordeals. To Brazilian women terrified of the rough examinations, inductions, forceps, episiotomies, and lack of labor support that often come with vaginal birth, cesareans can sounds like a pretty good deal. (Sounds a lot like the U.S. in the not-so-distant past, come to think of it.)

And Brazilian hospitals do their best to make sure the money-making surgery stays popular:

Safaris?

“Private clinics are often happy to make that dream come true by turning delivery into something akin to a weekend retreat in a birth-themed five-star hotel. At the Perinatal Clinic in Rio de Janeiro, mothers can get free hairstyling, manicures and makeup sessions, and for a fee, can have their rooms decorated in a safari or teddy bear motif. Once the new mom is ready for visitors, a catering service complete with waiters can also be arranged.”

Teddy bears? Waiters? Dang! I want a c-section, too!

The times appear to be a-changin’ for real. In the last year and a half the Brazilian government has put over a billion dollars into a program designed to “humanize” natural birth. Whether that will make a real dent in Brazil’s cesarean-saturated medical culture, though, remains to be seen…

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“Optimal Care in Childbirth,” by Henci Goer and Amy Romano: A review

I’m a pediatrician. My interest in childbirth, from the time I finished my obstetrics rotation in medical school until I began writing my book, Birth Day, in the mid-2000s, was focused on what I needed to know in the course of preparing for the arrival of a sick newborn. What’s the gestational age? Any maternal illnesses? How’s the fetal heart tracing? Then I’d set out my tools and watch and wait until my new patient emerged from his mother.

I confess I did not give much thought to what was being done to the mother in the course of her giving birth, whether it was an induction, an episiotomy, or as happened more and more frequently over the years, a cesarean. Babies were my business; I was only peripherally aware of any obstetrical controversies smoldering behind the scenes.

My research for Birth Day was a crash course in the science and politics—especially the politics—of childbirth. I was introduced to the deep divide between what I’ve come to think of as the right and left wings of American maternity care.

At the extremes I saw a clash of incompatible cultures: the “all technology, all the time” (right-wing) camp–which viewed childbirth as a potentially lethal affair and managed laboring women accordingly–versus the solo, unassisted (lefty) birthers whose only desire was to be ignored by doctors and their interventions as nature took its wise, benign course. From many of the the emails I received from Birth Day readers, there really didn’t seem to be much in between.

The research literature of childbirth is the battlefield on which these “baby wars” have long been fought, a landscape littered with studies–some excellent, some awful–that support just about any conclusion an observer might want to make. Take a hot-wire topic like cesarean section. Depending on the biases and prejudices of the author, the same operation can be an unqualified boon to mankind or the devil’s own handiwork. Separating the research wheat from the chaff, the solid evidence from the cherry-picked, can be a daunting task.

So where can a maternity care provider turn for reasonable and reasoned advice? In their new book, Optimal Care in Childbirth: The Case for a Physiologic Approach (Classic Day Publishing), Henci Goer and Amy Romano seek to be that go-to resource—and they succeed.

Professional life has not been easy for Goer and Romano. In the introductory chapters of Optimal Care they describe the conflict between the birth-as-pathology-oriented medical management (MM) model of care so prevalent in the U.S. (the obstetric right wing, in my mental construct), and the low-intervention physiologic care (PC) model that emphasizes birth as a normal event and a major life milestone marking

Henci Goer

the transition to parenthood. Despite the authors’ declaration that “every group that has ever set out to design a healthy maternity care system has articulated the principles and practices” of the PC model, change in the American way of birth has been slow and incremental.

“The [PC model] wheel has been reinvented repeatedly, yet somehow we cannot get it rolling. The obvious question then becomes, Why not?”

Goer and Romano then line up the suspects, usual and not, for the maddeningly unmovable status quo. There’s money, of course—the perverse economic incentives that support hospital maternity wards and the expensive technologies that come with them—and the inertia of entrenched habits and practices. Too, there is the belief held by many women, often reinforced by their maternity care providers, that their bodies are not competent for the task of giving birth.

Interestingly, Goer and Romano also cite the rise of “evidence-based decision-making” in medicine (or, as the late Canadian obstetrician Phil Hall described it, “decision-based evidence making”) as a self-reinforcer of conventional obstetric care. When an evidence-gathering framework designed to evaluate the treatment of  illness is instead applied to a normal physiologic process, the result is an increasingly narrow definition of “normal” and a much broader one of “pathology.”  Of such thinking, the authors conclude, comes the likes of early labor induction, routine episiotomies, and skyrocketing cesarean rates—and the incredibly difficult task of trying to change an obstetric culture so committed to the MM model that the benefits of all births being cesareans is actually considered a legitimate topic of discussion.

“By now you may be thinking that the situation is hopeless; resistance is futile.”

Well, yes, that thought does cross a reader’s mind. The research deck does seem to be stacked in favor of medical management. So, given decades of crying in the childbirth wilderness, what keeps Goer and Romano going? Why haven’t they surrendered to the inexorable march of techno-birthing? How have they not gone completely nuts?

“It is not [hopeless],” Goer and Romano insist, “but those wanting to reform maternity care need a solid foundation in what the obstetric evidence does, does not, or only seems to support, as well as an

Amy Romano

understanding of the impediments to change…”

In other words, you have to fight “science” with science, and that is what Goer and Romano do so well in this fine book.

Optimal Care is a hefty volume–nearly 600 pages—and not every reader will want to plow through it from start to finish. There’s really no need to, though—the book’s structure invites focused reading. Each of its eight sections is divided into chapters that hone in on specific aspects of a more general topic. A reader interested in the subject of episiotomies, say, need read only the twenty pages of Chapter 15 to learn why episiotomies are rarely necessary, and why, despite that evidence, they are still commonly performed. Meanwhile, those who wish to read about a more complicated topic like cesarean section will find an in-depth discussion of the science and politics of that surgery spread over the three chapters of Section II, “The Cesarean Epidemic.”

I found two features of Optimal Care in Childbirth particularly helpful for busy clinicians. At the end of each chapter are concise, bulleted “Strategies for Optimal Care” designed to promote physiologic birth in a variety of settings.  Following that are “Mini-Reviews”—summaries of topic-related research which include, notably, the authors’ reasons for including and excluding certain studies. Goer and Romano are refreshingly upfront about their PC model biases—literally from page one—an honest and rare thing to see in the highly polarized world of modern maternity care.

Optimal Care in Childbirth is a welcome addition to the ever-expanding library of maternity care books. By using science in the service of physiologic birth, Henci Goer and Amy Romano offer a welcome push-back to the all too common view of uncomplicated childbirth as a disaster just waiting to happen.

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Filed under Book review, Cesareans, Maternal-child health, Natural childbirth, Politics

More on cesareans and obesity

Cesareans? Really?

Does cesarean birth put a baby at increased risk for obesity in the future? Seems a little far-fetched at first glance, but Dr. Susanna Huh and her Harvard colleagues just published a study that makes the link a bit more “near-fetched.” (The study itself is available here.)

Huh’s team found that children born by cesarean section were twice as likely to be obese at 3 years of age than were those born vaginally. This relationship held up even when factors like the mother’s weight, ethnicity, age and how many babies she’d already had  were taken into account. Interestingly, it didn’t make a difference whether the cesarean was performed before or after labor started.

The study wasn’t designed to look at the reasons for the increased risk in obesity, but the Harvard team suggested several possibilities:

The first is the alteration of the gut microbiota–the sum total of all the bacteria found in the human bowel–caused by a cesarean birth. (More detail on that here and here.) This alteration can lead to low-level inflammation in the bowel which is associated with obesity.

The second possibility is that cesarean birth is just a stand-in for something else that’s happening at the same time. In this case, Huh and colleagues wonder about all the antibiotics given to women who are having cesareans. Antibiotics are known to alter the gut microbiota, but research results are mixed as to whether this is a lasting effect.

Finally, it’s possible (though unlikely) that all of this has nothing to do with the gut microbiota. There are hormones and other factors related to inflammation that surge in a mother’s bloodstream (and her baby’s) during labor, and these, obviously, are missing if a mother undergoes a cesarean before she starts labor. The lack of maternal stress response during labor could adversely impact the development of the newborn immune system, leading to the inflammation associated with obesity.

My best guess: it’s a big moosh of all of the above, plus other factors no one has even dreamed of yet. In the meantime, the issue of increased obesity risk is one more thing physicians and pregnant women should consider before deciding on how a baby is to be born.

It’s a complicated matter, this business of hatching healthy humans…

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Cesareans and asthma: More evidence

No way to spend a childhood...

Yet another study links cesarean birth with asthma. This one involved 37,000 participants in the Norwegian Mother and Child Cohort Study, and compared cesarean- and vaginally-born children for evidence of asthma at age 3. Those born by cesarean section had an increased risk of asthma.

The authors speculate that the altered gut microbiota found in cesarean babies–the collection of bacteria that live in the bowel–may be the reason for the association. (See my posts here and here for an explanation of how and why an altered gut microbiota may be at the root of a number of later chronic illnesses.)

The study’s authors described the increased risk as “slight,” which contrasts with the “moderate” risk found by other researchers. This apparently lower risk may be due in part to the how the study was performed.

First, the researchers lumped all cesareans–both scheduled cesareans and those that followed a long labor, in which a baby may be exposed to the normal bacteria of the birth canal–rather than comparing scheduled cesareans to vaginal births. The latter comparison would give a clearer picture of childhood asthma risks from cesarean birth.

Second, the study only follows the children to 3 years of age. Many cases of asthma occur later in childhood, and a longer follow-up of these children (which is no doubt in the works) would give a clearer picture of the risks.

Studies like this one add more weight to the argument for reducing the number of cesareans currently being performed, particularly those done without any medical need. Women should be informed of the potential long-term health risks and benefits for their children when choosing how and where they want to have their babies.

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Filed under Asthma, Cesareans, Natural childbirth