Tuesday, May 3, 2016


Co-authored by Emily Pereira, Anthropology major, University of Rhode Island

When I was pregnant, the human microbiome was hot. And news about the microbiomes of newborns was even hotter, at least to my eyes and ears because I was on the verge of having one.

This was in 2014. Studies were starting to find that babies born via c-section have different microbiomes than babies born vaginally. These findings were being interpretively linked to health problems down the road. 

Here’s a write-up of one study of a few 4-month-olds that I came across while pregnant: “Infant gut microbiota influenced by cesarean section and breastfeeding practices; may impact long-term health

And today studies continue to pop-up that find differences in baby microbial composition and then suggest those differences may be linked to future health problems. For example, here’s a recent one from 2016 in JAMA Pediatrics
“CONCLUSIONS AND RELEVANCE The infant intestinal microbiome at approximately 6 weeks of age is significantly associated with both delivery mode and feeding method, and the supplementation of breast milk feeding with formula is associated with a microbiome composition that resembles that of infants who are exclusively formula fed. These results may inform feeding choices and shed light on the mechanisms behind the lifelong health consequences of delivery and infant feeding modalities.”
These discoveries about c-sections seem important because microbes are now famous for being linked to all kinds of health troubles. 

According to the American Microbiome Institute... 
“studies are finding that our bacteria (or lack thereof) can be linked to or associated with: obesity, malnutrition, heart disease, diabetes, celiac disease, eczema, asthma, multiple sclerosis, colitis, some cancers, and even autism.”
And of course many of those same things have been epidemiologically traced back to birth by c-section. Here’s a report on one study, “published in the British Medical Journal, [that] found that newborns delivered by C-section are more likely to develop obesity, asthma, and type 1 diabetes when they get older.”

Another found that, “people born by C-section, more often suffer from chronic disorders such as asthma, rheumatism, allergies, bowel disorders, and leukaemia than people born naturally."

One can’t help but assume it’s all connected. If microbes are to blame for this list of problems and if c-sections are too and if c-sections are causing babies to have different microbiomes, then the following conclusion seems like a no-brainer: we need to be wiping c-sected babies with their mother’s vaginal juices.

So although I did basically nothing to prepare for a c-section (d’oh!), I imagined that if my childbirth came to surgery, that it would be really easy to avoid the risks to my baby's health by simply wiping him down with something soaked in my lady fluids.

I had even caught wind of a trial of this procedure, written-up somewhere, and so I mentioned it to my OB at a prenatal visit. She said she’d heard of it and that there was a term for it but the term escaped her. The idea excited her, but it wasn’t even remotely close to being part of regular clinical practice yet. Remember, this was summer 2014. Sensing it was too soon and out of reach, I changed the subject of conversation. Yet, I continued to believe that someone would just help me out with the whole vaginal swabbing thing if need be. It seemed simple enough. No biggie.

At the time, I didn’t Google around for tips or instructions so I don’t know what the Internet was offering up to would-be mothers/vaginal-microbe believers like me. But today it’s quite easy to find encouragement to D-I-Y transform your kid’s c-sected microbiome into a naturally-born one.

Here, let Mama Seeds explain:
“In the event of a c-section, be proactive. Mamas, we know this recommendation is not without its “icky-factor," but WOW it makes perfect sense when you think about it, and some believe it will be a standard recommendation in the future. Here goes: if your baby is born via c-section, consider taking a swab of your vaginal secretions and rubbing it on your baby’s skin and in her/his mouth. I know, ick. But when babies traverse the birth canal, they are coated in and swallowing those secretions/bacteria in a health-promoting way, so all you’re doing is mimicking that exposure. Don’t be afraid to ask your midwife or OB to help you collect the vaginal swabs—or do it yourself, if you’re comfortable. You have all the available evidence on your side.” - Michelle Bennett, MD is a full-time pediatrician, a Fellow of the American Academy of Pediatrics, a mother of two, and a founder of Mama Seeds.
Like I said, I didn’t have Mama Seeds. But I didn’t need Mama Seeds. While I was being wheeled into emergency cesarean surgery, I still shouted “SEED MY BABY WITH MY VAGINAL MICROBES!”

The reaction from the hospital staff? There was no reaction and, surprise surprise, there was no artificial seeding of my baby’s microbiome.

And that’s good. That’s how it should have gone down because my request was not based on scientific thinking. I hope you'll forgive me. I was pregnant. I wasn’t myself.

Slowly I’m becoming myself again, though, and thanks to a keen student, Emma Pereira, this post’s co-author, I’ve learned quite a bit about the science behind whether I should have seeded my newborn with my vaginal microbes. And the answer to anyone who’s wondering is a resounding NO. At least for now.

Here’s why.

1.   We don’t know if it’s necessary. Despite the increasing numbers of studies, no one to our knowledge has looked longitudinally at the microbiomes of humans born via c-section to find out if the changes detected (in very small samples) early on in these studies actually last, let alone if they can be causally linked to differences in health. It seems like the money and the technology is there to identify (via genetic sequencing) myriad microbial species, but the time and energy just isn’t there to do much else. So, although there is a growing literature, the dots aren’t connected yet. A graphic may help explain what we've learned: 

2.  You could actually harm your baby. Because there is currently no known good to come of seeding one’s c-sected baby with one’s vaginal microbes, there can only be bad. Yes, authors of this study published recently in Nature Medicine took a bunch of gauze that had been sitting in the mother’s vagina for an hour and swabbed 4 babies for a duration of about 15 seconds right after their birth by c-section and then found a significant difference in their microbiome at 30 days-old compared to babies who weren’t treated.  The microbiome wasn’t identical to vaginally born babies, but at least it wasn’t identical to those poor c-sected controls who didn’t get swabbed, right? Well, maybe wrong. First, please revisit number 1. And, second, maybe causing a baby to have a c-sected microbiome is not worse than seeding a baby with genital herpes, which is a very real possibility in practice, outside of these early, highly controlled pilot studies. As reported in Should C-section babies get wiped down with vagina microbes?“the procedure could unknowingly expose newborns to dangerous bugs, pathogens that babies born by C-section usually avoid. Group B streptococcus, which is carried by about 30 percent of women, can trigger meningitis and fatal septicemia... Herpes simplex virus can lead to death and disability in newborns. And chlamydia and gonorrhea can cause severe eye infections.”

So, again, as of right now, there is no reason to seed one's c-sected baby with one's vaginal microbes. And there are very good reasons not to! 

We think that the temptation to blame the rise of numerous complex health problems to something as simple (and easily knowable) as the way we’re born is similar to the temptation to reduce these very same complexities to what’s coded in the genome. For some people, maybe even many, it may turn out to be this simple! But we’re far from knowing whether that’s true. 

Spare your baby from meddling with his microbes until the evidence is there. 

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