Tag Archives: Caesarean section

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.

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*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

Cesareans and chronic childhood disease: Time for a public discussion

From the Ishinhō, Japanese medical text, 1860

From the Ishinhō, Japanese medical text, 1860

In an analysis published in the most recent edition of The BMJ, Drs. Jan Blustein and Jianming Liu examine the evidence that cesarean delivery is associated with an increased risk of chronic childhood diseases like asthma, type 1 diabetes, and obesity. Their conclusion: the bulk of the evidence suggests that the association is real.

The time has come, Blustein and Liu write, for maternity care providers to include the risk of chronic childhood disease in their discussions with women considering a “non-essential” cesarean, such as when the choice is between a VBAC or repeat cesarean, or in the case of a woman choosing a medically unneccessary cesarean in lieu of vaginal birth—the so-called “maternal request” cesarean.

This topic has intrigued me for some time now. As part of my recently completed MPH program at the University of Minnesota, I wrote a paper titled, “Do Cesarean Sections Increase the Risk of Child Asthma? A Systematic Literature Review.”

In writing the paper I read and analyzed every research study on the subject since 2001. Roughly two-thirds of those studies detected a small-to-moderate association between cesarean birth and childhood asthma. (In fact, 90% of the studies detected an association between the two, but not all were statistically significant.) Most of the studies that didn’t find the association were seriously flawed—too few subjects, for example, or ignoring possible confounders, like prematurity or a history of maternal asthma. Three meta-analyses (two in 2008, one in 2014) all reached similar conclusions: cesarean section is associated with about a 20% increase in the risk of child asthma.

My paper was limited to asthma, but as described in the BMJ analysis there’s evidence that cesareans increase the risk of other chronic childhood illnesses, too–type 1 diabetes and obesity. A 2015 study by Sevelsted et. al. analyzed a cohort of two million Danish children and found small-to-moderately increased risks of juvenile rheumatoid arthitis, connective tissue disorders, inflammatory bowel diseases, immune deficiencies, and even leukemia.

Given that body of evidence, you’d think that organizations like ACOG (the American Congress of Obstetricians and Gynecologists) and the U.K.’s National Institute for Health and Care Excellence would be pushing their members to share this information with their pregnant patients. But they’re not. According to Blustein and Liu,

“…knowledge about chronic disease risks could affect decision making in non-essential caesarean. The American College of Obstetrics and Gynecology and the UK’s National Institute for Health and Care Excellence recently issued consensus statements on caesarean delivery at maternal request. Based on evidence about maternal and perinatal outcomes, both groups concluded that a pregnant woman requesting caesarean should have that choice, if she still desires it after discussion of the risks and benefits of the procedure. Importantly, neither group acknowledged the long term risk of chronic disease. [Emphasis mine.]

Critics can (and do) point to the uneven quality and designs of the studies that support such links—it’s association versus causation all over again—but that’s not entirely fair. To prove beyond doubt that cesarean birth increases the risk of child asthma, you’d have to do trials where women are randomly assigned to cesarean or vaginal birth…which, as you can imagine, is a practical and ethical non-starter. That leaves us with observational studies, which can only point out that two things seem to be related, not that they definitely are.

Ah, but there has been a randomized study of the long-term effects of cesareans versus vaginal birth in term, breech deliveries, and at least one research team has made the case that randomized trials of mode of delivery aren’t really unethical. More on those topics soon.

Finally, just to re-re-reiterate: I’m not anti-cesarean. My wife and son are alive and well today thanks to a medically necessary cesarean. But the cesarean rate today is 6 times higher than it was when I was a junior in high school (1970, if you must know…). As Blustein and Liu point out in their analysis:

“We live in a world where caesarean rates cannot be explained by compelling medical indications.”

Perhaps increased awareness of the potentially negative impact of cesareans on child health will help reverse that decades-long trend.

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Filed under Asthma, Cesareans, Diabetes, Obesity, VBAC

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

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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Things Kids Say: The ABC’s of surgical birth

Thinking, thinking…

“So that makes me the B-section.”

Will, age 6, explaining that since his newborn brother was born by C-section, his big sister must have been an A-section, which logically left him in the alphabetical middle of the birth order.

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Photo by estoril

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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