Experts Voice Concern Over 'Seeding' Birth Trend

Think swabbing C-section babies with mom's vaginal secretions sounds icky? A new scientific article says 'seeding', the latest birth trend, is actually unsafe.

Experts Voice Concern Over 'Seeding' Birth Trend fred goldstein/Shutterstock

Many C-section mothers worry that their babies miss out on a lot—no immediate skin-to-skin contact or breastfeeding, separation as the baby is taken away to the nursery, even the lack of cleaning out of baby's lungs by being squeezed down the birth canal. More and more moms, though, are demanding "natural" C-sections, and hospitals are responding by changing their protocols. But one practice that's gaining popularity should actually be restricted, say top doctors from the U.K. in an editorial in the British Medical Journal (BMJ): vaginal seeding, or swabbing C-section babies with mom's birth canal fluids.

Can vaginal fluids fight disease?

In vaginal seeding, gauze is placed in the mother's vagina and then rubbed on a baby born via C-section, exposing him to the fluids he would otherwise have come into contact with during a vaginal birth. The theory is that bacteria in the vagina is crucial for developing baby's microbiome, a collection of tiny organisms in the body that strengthens the immune system and help fight off disease—an advantage C-section babies are lacking.

The editorial's lead author, Aubrey Cunnington, M.D., and his colleagues agree that the idea of vaginal seeding has merit. "Yes, in theory vaginal seeding could alter the risk of diseases in later life, but we are many steps away from having the evidence to prove this," Dr. Cunnington, a clinical senior lecturer in Pediatric Infectious Diseases at Imperial College London, tells Fit Pregnancy. "There are some diseases like obesity, allergic and immune disorders which have been associated with C-section births," but this is only a link, not a cause and effect. There could be something else at play, "for example a common factor that puts mothers at higher risk of needing a C-section and their babies at higher risk of developing these diseases in later life," he says.

Unproven benefits, real risks

So why not go ahead and swab away, just in case it helps? The problem is that vaginal secretions can also transmit infections, specifically group B strep and sexually transmitted diseases like herpes, gonorrhea and chlamydia. Pregnant women in the U.S. are screened for group B strep, which 20-30 percent carry (they are not screened in the U.K.). Additional screening could help mitigate the chance of infection, although Dr. Cunnington says it might be difficult to catch all cases. "It would need to account for the fact that any of these infections can be acquired during pregnancy, and detection of group B strep carriage can be intermittent, so screening would need to be pretty close to the time of delivery," he says.

Plus, C-section babies who are exposed to vaginal fluids risk additional infections. "We are also increasingly concerned about babies becoming colonized with antibiotic resistant bacteria from their mothers," Dr. Cunnington says. "This is a particular problem for sick and premature babies in neonatal intensive care units."

Of course, babies who are born vaginally run this risk anyway, but Dr. Cunnington says that's no reason to increase it for babies born via C-section. "We think vaginal seeding could produce a similar risk of transmission of bacteria and viruses to vaginal birth; possibly the risk is lower," he says. "The short answer is that we don't know for sure because no one has done the research to find out. But the important point here is that C-section does result in a lower risk of infection for the baby, and there is an ethical question of whether it is right for a doctor or midwife to potentially increase that risk of infection by performing vaginal seeding."

Studies on the horizon

The question of evidence is at the crux of Dr. Cunnington's argument against vaginal seeding: It hasn't been proven to work, so it's not worth the risk. "There is no direct evidence that it produces any health benefit, [but] there is good reason for concern that vaginal seeding could transfer harmful bacteria or viruses to a baby who would otherwise not be exposed," he says.

A recent small study by Maria Dominguez-Bello, Ph.D., and colleagues, though, does give the first shred of proof to the theory of vaginal seeding. "The study shows that vaginal seeding does change the microbiota of babies born by C-section, making the microbiota more similar to that of babies born by vaginal delivery, [but] it doesn't tell us that this microbiota is any 'better' than without seeding, and it doesn't provide any evidence of a health benefit—it is just proof of concept," Dr. Cunnington says. He admits, though, that the study holds promise. "This seminal study is the first step in a long journey to test the hypothesis that vaginal seeding has health benefits." Dominguez-Bello agrees with Dr. Cunnington that more information is needed. "Our work only demonstrates bacterial restoration and there is the need of a big study that follows infants for enough time to measure health outcomes," she says. "Until then, we can only hypothesize that the microbial restoration is beneficial."

Should you seed yourself?

Because it's easy to do, women could choose to perform vaginal seeding themselves, but Dr. Cunnington says doctors shouldn't be pressured into doing it to avoid women taking matters into their own hands. Instead, he advises women to breastfeed and avoid antibiotics if possible. "Breastfeeding also has a powerful effect on the microbiota, and has proven health benefits," he says. "Antibiotic exposure in pregnancy and early life also alters the microbiota."

Although vaginal seeding is an interesting concept, Dr. Cunnington says there just isn't enough evidence to recommend it yet. "We are concerned that vaginal seeding is increasing in popularity despite the risk of harm and lack of evidence of benefit," he says. "We believe that health professionals and pregnant women need to be fully informed of the pros and cons."