Here's What You Need To Know About The Bacteria In Your Vagina

A microbiome doesn't just exist in your gut.
Vagina-themed cookies.
Melanie Dawn Harter via Getty Images
Vagina-themed cookies.

You’re probably aware you have a microbiome in your gut teeming with (hopefully) healthy bacteria that may help with everything from preventing obesity and digestive diseases to reducing the risk of anxiety and Parkinson’s disease, as well as some cancers. But your gut is not the only place where bacteria thrive in the body.

Communities of bacteria ― scientifically referred to as microbiota or your microbiome ― exist all over the body, including in the vagina, according to Jacques Ravel, a professor and associate director for genomics at the Institute for Genome Sciences at the University of Maryland School of Medicine.

“They exist in all the areas that are exposed to the environment” or can be when foreign things enter, as in the case of the gut, Ravel told HuffPost.

And just like having the right healthy bacteria in the gut is important, having the right bacteria in the vagina can have an effect on health, too. While research on the vagina’s microbiome is still in its early days, there are some things experts do want patients to understand about the bacteria down there.

Here’s a breakdown of what you should know:

1. Some vaginas have bacteria related to the bacteria in yogurt ― and that type is considered ‘good’ bacteria

One type of bacteria found in some vaginas is from the same genus as the bacteria in the yogurt in your refrigerator: lactobacillus. Every genus has many species within it. And the specific species of lactobacillus that can be found in the vagina is different from the species found in the gut, urinary tract and some yogurts, Ravel explained.

There are many types of bacteria that can live in the vagina, but if you have lactobacillus, you’ve won the vaginal microbiome jackpot, according to Ravel.

2. Healthy bacteria can lower your risk for sexually transmitted infections

Having lactobacillus is linked to a lower risk of infections from STIs like chlamydia, gonorrhea and HIV, as well as a lower chance for other problems, including pelvic inflammatory disease.

Scientists like Ravel think that’s because lactobacillus produces a lot of lactic acid, lowering the vagina’s pH level to about 3.5 or 4 (which makes it very acidic). And an acidic environment is a hostile one for infections, Ravel explained. And that’s a good thing.

“[The vagina is] an open site, just like the mouth or anything, meaning that you can have a lot of invading bacteria,” he said. But lactobacillus, by making the vagina acidic, protects against all of that.

Another infection lactobacillus helps prevent is bacterial vaginosis. It’s very common and can cause pain or itching in the vagina, an odor and a white or gray discharge (and increased risk of other infections or complications if left untreated). Antibiotics can help, but once a women gets this infection, she’s more likely to get it again and again, Ravel said.

Many women ignore the symptoms or don’t realize they’re something to tell their doctor about. (And most gynecologists don’t routinely look for the infection ― so if you do suspect something’s up down there, say something!)

3. Good bacteria may help prevent preterm labor

Several studies suggest that pregnant women who have lactobacillus in their vagina are less likely to deliver their baby prematurely. One such study of 49 pregnant women linked lactobacillus to a lower risk of preterm labor and showed that women with two other species of bacteria, gardnerella and ureaplasma, were most likely have a preterm birth.

But other studies contradict those results, Ravel added. And other research suggests that race may explain why lactobacillus can help prevent premature births for some women and not for others.

“I think the association is a lot more complicated than we think,” Ravel noted ― “prematurity being such a multi-factorial, multi-causal condition.”

4. A lot of women don’t necessarily have good vaginal bacteria

A lot of women don’t have lactobacillus in their vaginas. They have microbiomes down there that look entirely different with a lot more variety of bacteria and a lot less (protective) acidity, added Richard Cone, a professor of biology and biophysics in the biophysics department at Johns Hopkins University.

“All of these women are at markedly increased risk of acquiring STDs, including HIV, and when they become pregnant are at higher risk of premature births and perinatal infections,” he told HuffPost.

Data that Ravel and his colleagues have collected show more than 25 percent of women have no (or low levels of) lactobacillus in their vaginas ― and that number jumps to more than 40 percent for Latinas and just under 40 percent for African-American women.

But that doesn’t mean those women’s vaginas are unhealthy, Ravel added ― they’re just at higher risk for all of those problems lactobacillus protects against.

5. Your mom may be to blame for whatever your vagina’s microbiome looks like

There’s evidence that having good vaginal bacteria can be passed down from mother to daughter. Not because you’re born with certain genes but because if a baby girl is delivered vaginally, she’s exposed to her mother’s vaginal bacteria at birth. If the mom has good bacteria, it may precondition the baby to grow good bacteria later on (since vaginal bacteria doesn’t tend to accumulate until puberty), Ravel said.

The problem is that would mean that babies delivered via C-section or to mothers without lactobacillus would be less likely to grow that good vaginal bacteria later on.

Some babies born via C-section still end up with lactobacillus in their vagina, though, Ravel said. So, even though the connection makes sense, it’s tough to know with certainty how important that link is. More studies are needed but ethically are tough to do, Ravel said.

6. Birth control can change the bacteria in your vagina

Some types of estrogen-containing birth control, like some birth control pills, can help encourage lactobacillus to grow and spread in the vagina, Ravel said. That’s because estrogen is what encourages growth of any vaginal bacteria ― and why women don’t tend to get a lot of bacteria in their vagina until puberty.

Other types with progesterone, like Depo-Provera, have been associated with increased infection risk, according to Ravel. Researchers are currently investigating whether that might be because those birth control methods discourage the growth of healthy, protective bacteria, he added.

7. Having sex can change the bacteria in your vagina

Men have bacteria on the penis, and those microbes look a lot more similar to the communities of bacteria found in women without lactobacillus. They can be transferred when you have sex ― and, if they do, they tend to wipe out any good bacteria you have.

Studies that have followed women over the course of several weeks (for which the women had their vaginas swabbed and the microbiota analyzed, and the women also reported sexual activity and hygiene) have shown that the non-lactobacillus bacteria can take over the microbiota in the vagina in a very short amount of time (eliminating lactobacillus) ― in some cases, by the next day.

That doesn’t mean that having sex will necessarily get rid of good vaginal bacteria if you have it, but it might, Ravel said. Using a condom helps block the spread of those bacteria.

8. Vaginal douching can get rid of good vaginal bacteria, too

You do not need to clean your vagina. Use a gentle soap and water to wipe around the exterior areas ― and anything farther up cleans itself.

One study followed 3,620 women for a year, testing the women every three months for the bacterial vaginosis infection. Women who reported vaginal douching were more likely to be among the 40.2 percent of women had the infection at some point over the study.

9. Scientists are working on a probiotic for your vagina

Ravel’s lab, as well as another company in California, are developing probiotic treatments (basically a concoction of bacteria from healthy women with lactobacillus, Ravel explained) that could be administered directly to the vagina to allow healthy lactobacillus bacteria to colonize and take over any woman’s vagina.

The challenge is finding the right type of lactobacillus that’s able to actually do that, since many strains are too weak. There’s also a challenge in determining if it would work for all women.

Other companies are working on a similar treatment that would be given orally as a pill. None of those treatments are ready for prime time yet, Ravel said ― but he’s hopeful. “I think those solutions are coming.”

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