Move over, placenta eating — there’s a new player on the newborn scene, and its name is vaginal seeding. In case this practice hasn’t crossed your radar yet, it’s a practice involving transferring bacteria from a mother’s vagina to a newborn who was delivered by C-section. Before you stop reading because you think that sounds gross, remember that the majority of babies pass through the vagina on their way into the world. (It’s also how they got there, if you know what I mean.)

We are all teeming with bacteria. There are hundreds of trillions of them living on your skin, in your gut, and–yes–in your vagina (if you have one). Collectively, these microbes are called your “bacterial flora,” and each person’s flora is unique (who knows, maybe some day we’ll use them like fingerprints). These microscopic creatures outnumber your own cells, and while there’s currently a tremendous amount of research into this topic, we are only beginning to understand how they interact with our bodies.

One thing we do know is that certain diseases (primarily autoimmune and allergic diseases) are associated with specific patterns of bacterial flora. This has to do with how the bacteria living inside your gut interact with your immune system–essentially training it to tolerate or attack certain things. Researchers are currently working on how modifying the gut flora may help to prevent or cure a variety of diseases, and it’s a field that looks pretty promising (although there are a lot of kinks left to work out).

Vaginal seeding came about because of the realization that infants who are born by Cesarean section tend to have gut flora that resembles that of their mother’s skin, while those born vaginally are colonized with bacteria similar to that found in the mother’s vagina. And there’s a limited amount of evidence that children born by cesarean delivery are at higher risk for allergic diseases. So it certainly makes sense that, for those infants who were born without exposure to the mother’s vaginal flora, vaginal seeding may be beneficial. Maybe.

Moms across the country — as well as some health care providers — have taken this concept and run with it, and there’s very little anyone can do to stop them. It’s not like we’re talking about a prescription medication or a surgical procedure; you just stick a swab in there and rub it all over your baby. Certainly the kind of thing most moms could pull off at home.

So like so many things in parenting, it comes down to making an informed decision about whether this treatment is the best decision for your child. And while there is some plausibility to these claims, they haven’t been proven. While vaginal seeding attempts to replicate the exposure of a vaginal delivery, I think we can all agree that the two are not equal. We haven’t yet shown that this procedure has a real benefit, or how big that benefit may be. So that’s all a bit of an unknown, but one with some promise.

Here’s the thing, though: Vaginas don’t harbor only beneficial bacteria. There are villains among the heroes, and swabs don’t discriminate. The most common causes of neonatal sepsis (overwhelming infection that is fatal in many cases) are organisms that the infant picked up on the way out. Here’s a quick (and incomplete) list of some things to consider:

Group B Strep (GBS). Mothers in the U.S. are routinely tested for this bacteria, and about 1/3 of them have it. GBS lives in the vagina without causing any problems, but it doesn’t play nicely with babies. It’s a major cause of neonatal bloodstream infections and meningitis. Mothers who have been found to carry this bacteria are treated with antibiotics during labor–an intervention that has reduced the rate of neonatal sepsis and saved a lot of babies’ lives. But even if mothers receive antibiotics during labor, we don’t know that her bacteria counts will still be low hours or days later when she decides to seed her new baby.

Herpes simplex virus (HSV). This virus is spread sexually and usually causes painful lesions in the genital area. Once a person is infected, the virus is there for the long haul, usually causing periodic outbreaks. But sometimes people are infected without developing symptoms, so the fact that you’ve never had an outbreak doesn’t mean that it’s not there. HSV can cause some truly devastating disease in newborns–we’re talking fine to dead in a matter of hours. It’s not pretty.

Chlamydia and gonorrhea. These are two sexually transmitted bacteria that wedo routinely screen for during pregnancy. Chlamydia can cause pneumonia, but the big concern here is an eye infection that can cause permanent blindness (it’s the reason for using erythromycin ointment after birth). In theory, if the mom tested negative and is in a monogamous relationship (with someone who is also in a monogamous relationship), the baby should be at pretty low risk. But tests can be wrong, and people cheat. It’s a messy world.

Human immunodeficiency virus (HIV). This is a complicated topic, and the risk for transmitting HIV from a mother to a baby depends on the mother’s viral load and what medications she is on. Sometimes, a cesarean delivery is performed to decrease the risk of infecting the baby. Now, I really hope that after the OB/GYN talks about this and cuts a woman open to get the baby out without exposing it to HIV, the mother wouldn’t decide to go the route of vaginal seeding. But I’ve been disappointed before.

Just like the potential benefits, the potential risks are somewhat unknown as well. We don’t know how many babies who got “seeded” would develop infections from these organisms, how many of those infected babies would die or suffer significant harm, or what other potential complications there might be. Without more studies, we’re left to piece together little bits of evidence and use our best judgment. But if parents are going to assume the benefits are real, I think that they need to strongly consider the potential risks as well.

For parents who are considering this, it’s a good thing to discuss with your doctor who can make sure that you have all the testing and information you would need to make an informed decision about your specific situation. And for all parents of newborns — however your baby was born, and whether you’re a “seeder” or not — it’s crucial to be aware of signs of infection and to contact your pediatrician if you have any concerns about your baby’s health.

Chad Hayes is a pediatrician who blogs at his self-titled site, Chad Hayes, MD.

Image credit: Chad Hayes