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Katherine Martinelli

The Truth About Vaginal Seeding

Could boosting the immune systems of c-section babies be as simple as swabbing them with vaginal fluid at birth? Experts aren’t so sure.

Giving birth is a messy business. When baby emerges from a vaginal birth, she’s going to be far from pristine—in fact, she’ll be covered in bacteria-filled vaginal fluid. But studies suggest those microbes can actually play an important role in shaping a newborn’s immune system and helping baby ward off disease. So what about babies born via c-section? Because they’ve skipped a trip down the birth canal, instead of vaginal microbes, they pick up bacteria that live on mom’s skin, and, as research indicates, may be at a slightly higher risk for immune and metabolic disorders.

In an effort to pass on the same lasting health benefits of a vaginal birth to c-section babies, researchers have recently been exploring what’s known as vaginal seeding,or microbirthing—when doctors swab the mother’s vagina and wipe the vaginal fluid on baby’s body, face and mouth following a c-section birth. The practice, which was introduced just a few years ago, has been gaining in popularity, with doctors seeing the request pop up more frequently in patients’ birth plans. But the jury is still out on how safe and effective vaginal seeding really is, and many experts—including the American College of Obstetricians and Gynecologists—are encouraging women to steer clear until more research is done. Here’s what you need to know about vaginal seeding, including the possible benefits and potential risks.

What Is Vaginal Seeding?

About one third of all babies in the US are delivered via c-section, a procedure that can be lifesaving for both mom and baby. But experts have found that c-section babies and those born vaginally wind up with different microbiomes—the bacteria, fungi and viruses that live in and on our bodies. The bacteria in our microbiome help digest our food, produce key vitamins, regulate our immune system and protect against less benign bacteria that cause disease.

“There are some studies suggesting that infants born via cesarean delivery are at increased lifelong risk of autoimmune diseases, asthma and allergic diseases,” says Marina Maslovaric, MD, an ob-gyn at HM Medical in Newport Beach, California. That includes food allergies and hay fever. These children may also be vulnerable to both childhood and adult obesity. “The theory behind vaginal seeding is that by exposing the infant to vaginal microbiota, these risks would be decreased.”

A small 2016 pilot study published in the journal Nature Medicine set out to investigate whether it’s possible to encourage the same microbiome in c-section babies as the kind existing in infants born vaginally. And it found that researchers could, in fact, level the playing field—at least in the first 30 days of an infant’s life—by wiping c-section babies with vaginal fluid.

The study tracked 18 babies: seven were born vaginally and 11 via c-section. Of the 11, vaginal seeding was used on four babies. Doctors inserted gauze into the vaginas of participating moms shortly before their c-section, then removed the fluid-soaked gauze right before surgery got under way. Within a minute after birth, doctors quickly swabbed the babies with the gauze, covering their lips, face, torso, arms and legs, genitals, anus and back. The result? After a month, the babies who underwent vaginal seeding had gut, oral and skin microbiomes that more closely resembled the infants who were delivered vaginally than the c-section babies who didn’t receive vaginal seeding.

The news sparked significant media coverage and a lot of interest among parents—so much so that filmmakers Toni Harman and Alex Wakeford directed and produced a 2014 documentary on the practice, Microbirth, and wrote a book in 2017 called Your Baby’s Microbiome to explore the subject. They find the research to be promising. “If a baby misses out on receiving this critical bacteria in the narrow window that surrounds birth, this could have implications for a baby’s lifelong health,” they say.

Does Vaginal Seeding Work?

The short answer: Experts aren’t really sure. The pilot study looked only at four babies who underwent vaginal seeding and tracked only their first 30 days of life. Due to the limited data, the study authors acknowledged in their report that “the long-term health consequences of restoring the microbiota of c-section-delivered infants remain unclear.”

A subsequent study published in Natural Medicine in 2017 invites further doubt. It found that after six weeks, there wasn’t a big difference between the microbiomes of babies born vaginally versus those who received vaginal seeding after a c-section. “Any differences that may be detectable at the time of birth are limited to the skin and oral microbiomes, and there is no difference in the gut, even at the time of birth,” says Kjersti Aagaard, MD, PhD, one of the study authors and a maternal-fetal medicine specialist at Baylor Obstetrics and Gynecology at Texas Children's Hospital Pavilion for Women in Houston. She points out that the mother’s uterus isn’t a sterile place, so baby’s first exposure to bacteria doesn’t happen just at birth. “Interventions aimed solely at the time of delivery may be too little too late,” she says. “More research is needed in that regard.”

Vaginal Seeding Risks

Experts aren’t just doubtful of the efficacy of vaginal seeding—many are also concerned about potential dangers the practice can pose for babies. “It’s important to recognize that mothers can transfer pathogens [to their babies through this procedure], which can be completely asymptomatic in the mother but can cause severe consequences for the infant,” Maslovaric says. “These include group B streptococcus, herpes simplex virus, chlamydia and gonorrhea.” For those reasons, the ACOG recommends that vaginal seeding shouldn’t be performed until more data on the safety and benefits of the process is available.

The ACOG recommendation is a “conservative” one, at least in the eyes of Eden Fromberg, DO, a holistic gynecologist based in New York City. Vaginal seeding could pose a possible risk, she says, but “it could also be argued that the benefit of preventing allergy, asthma, autoimmunity and other illnesses for a lifetime is far more important than the small potential risk of infectious disease.”

Others prefer to play it safe, emphasizing that even if the theory of vaginal seeding seems biologically plausible, there’s a lack of scientific data surrounding the practice. “It has no proven efficacy and renders potential risk,” Aagaard says. “Thus, it should neither be recommended nor encouraged, and use should be strictly limited to research settings.”

Published November 2017

PHOTO: Getty Images