Watch Out for These 10 Threats to Your Vaginal Microbiome

The vagina is far from a passive element of female anatomy. Instead, it’s home to a concentrated community of microorganisms. On the one hand, this vaginal milieu can support a comfortable, healthy reproductive system, promote positive birth outcomes, and help protect against issues like STIs.^1,2 But when thrown out of balance, it can open the door to discomfort and disease.

The question then becomes: What can we do to keep this microbial landscape flourishing? Ongoing research is starting to provide an answer, teasing out how our day-to-day actions impact our vaginal makeup. There’s still so much to learn, but here are early insights on what throws off the vaginal microbiome, and how to keep yours in a steady, balanced state. 

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The Living Landscape of Your Vaginal Microbiome

The vagina is home to bacteria, fungi, and other microorganisms.^1,3 These microbes contribute to various physiological functions such as immune regulation, protection against pathogens, and maintaining vaginal pH.¹ 

“Bacterial communities in the human vagina have a critical role in protecting against infectious disease,” explains Ava Mainieri, Ph.D., a geneticist and evolutionary biologist specializing in female reproductive health.

You can think of this living landscape like a garden: When properly maintained, it’s productive, self-regulating, and naturally resilient against pests and invasive species. 

The scientific community is still unpacking a lot of unknowns about the vaginal microbiome. But so far, it’s been linked not only to your chances of developing a vaginal infection, but also to infertility, pregnancy loss, sexually transmitted infections (STIs), and possibly even some forms of cancer.^2,4,5,6 Needless to say, it’s a pretty vital ecosystem that we should all be talking about (and marveling at) a bit more.

A Snapshot of a Strong, Resilient Ecosystem

Unlike the gut microbiome, which will ideally be home to a wide array of bacteria, the typical vaginal microbiome is much less diverse. 

“In reproductive-age women, often it’s one group that dominates: Lactobacillus, usually hailed as the keystone species of the vagina,” Mainieri explains.

Lactobacillus bacteria produce lactic acid, creating an acidic environment (healthy vaginal pH ranges from 3.8 to 5.0 during reproductive years) that helps prevent the proliferation of harmful pathogens in the vagina.⁷ To carry on the gardening analogy, you can think of lactic acid as a natural pesticide that plants emit to ward off predators. Beyond maintaining proper acidity, lactobacilli also helps reduce inflammation in the vagina and help to maintain the integrity of the vaginal mucus barrier.⁸ 

Within the group, or genus, of Lactobacillus, there are many subgroups or species. The four most commonly found ones in the vagina are Lactobacillus crispatus, Lactobacillus jensenii, Lactobacillus gasseri, and Lactobacillus iners. Though these species all produce lactic acid, they possess slightly different properties, and L. crispatus seems to be the most protective against unwanted pathogens. 

Microbiome mapping projects have revealed that most people have a vaginal microbiome that is dominated by one of these four types of Lactobacillus species, though some are not. When someone’s vaginal microbiome is not dominated by these keystone species, they are more at risk of dysbiosis. 

What Is Vaginal Dysbiosis?

Disturbances like hormonal changes, sex, your period, and some medications can wipe out beneficial Lactobacillus species and throw your vaginal microbiome into a state of imbalance, or dysbiosis. 

“Vaginal dysbiosis is characterized by the loss of Lactobacillus species dominance and increase of microbial diversity,” says Mainieri. “Disruptions in microbial balance can lead to various infectious diseases.” In other words, without a strong array of natural protectors, your vaginal microbiome becomes more susceptible to developing illness when exposed to intruders. Bacterial vaginosis (BV), yeast infections, and trichomonas vaginalis (TV) are a few issues that can commonly arise out of dysbiosis.⁹

10 Things That Can Throw Your Vaginal Microbiome Into Dysbiosis

Several factors can influence the composition and stability of the vaginal microbiome—some of which are out of your control. 

Sexual activity, ejaculate, lubricants, antibiotics, copper IUDs, douching, smoking, and even stress can all influence the vaginal microbiome, explains Mainieri. “It is also impacted by changes across a woman’s daily life, shifting alongside hormonal changes such as menarche, menses, becoming pregnant, entering postpartum, hormonal experiences related to gender-affirming care, and being in menopause,” she says.

Let’s dig into what we know about how the vaginal microbiome shifts with various inputs, so you can tease out how to best protect yours. 

1. Your Period

Period blood is slightly alkaline, which can temporarily alter the vaginal environment and throw off your vaginal pH.¹⁰ The hormonal fluctuations that happen during the menstrual cycle can also impact the microbial makeup of your vagina.¹⁰ The hormone estrogen is responsible for promoting the production of a sugar called glycogen that helps keep your vagina healthy. It also helps lactobacilli bacteria protect your vagina from harmful bacteria. Research shows that the vaginal microbiome can shift throughout your cycle in response to estrogen dipping.¹¹ When levels of estrogen are low (like during your period), this leads to a higher bacterial diversity but fewer lactobacilli. However, too much estrogen can encourage the fungus Candida to overgrow. That’s why many people develop yeast infections right before their period.¹² 

The Isala project—a citizen science study of the vaginal microbiome of 3,043 participants in Belgium—also found that period products might alter the vaginal milieu. In this research, menstrual cups were positively associated with protective L. crispatus, while menstrual pads were negatively associated with the beneficial species.¹³ 

2. Menopause

During menopause, the levels of reproductive hormones like estrogen decline. Since estrogen plays a role in the production of glycogen, a key fuel source for Lactobacillus species, menopausal women tend to have fewer of these protective bacteria.¹⁴ As a result, the vaginal environment can become less acidic, making it more vulnerable to pathogens and infection-causing bacteria during this life stage. Menopausal women tend to be at higher risk of bacterial infections like BV and UTIs for this reason.¹⁴ The good news? Your risk of yeast infections doesn’t typically increase with menopause (there’s a silver lining). 

3. Pregnancy and Breastfeeding

During pregnancy, your body goes through numerous changes that can impact the health of your vaginal microbiome. Things like fluctuating hormone levels, vaginal mucus production, and lifestyle changes can all affect your vaginal flora. 

From the early months of pregnancy, your vaginal microbiome gradually shifts to become more stable.¹⁵ This shift is thanks to the lactobacilli, which dominate the vaginal microbiome in the first trimester. These tiny superheroes work hard to keep the vaginal environment inhospitable to potential pathogens, keeping both and your baby safe.

After delivery, though, your vaginal microbiome undergoes a significant shift, becoming less dominated by lactobacilli.¹⁵ Research found that this more diverse microbiome can persist for at least one year postpartum in some people, and possibly even longer.¹⁶ A more diverse microbiome that is low in protective lactobacilli may make postpartum people more susceptible to vaginal infections.⁸

4. Antibiotics

While antibiotics are effective at treating bacterial infections, they can also disrupt the beneficial bacteria in the vagina, leading to dysbiosis and increasing the possibility of recurrent infections.⁷ Studies demonstrate that over 50% of people who take antibiotics for BV have a recurring infection within a year, and antibiotics are also one of the most frequent causes of yeast infections.^17,18,19

5. Birth Control

Although hormonal birth control (like the pill) doesn’t directly cause yeast infections, using certain types of birth control can alter the bacteria and yeast in the vagina, making it easier to develop an infection. Similarly, there’s some evidence that having a copper IUD can increase your likelihood of getting BV.²⁰ That said, more research is needed to fully understand how birth control impacts the vaginal microbiome. 

6. Sex

Sexual activity of any kind can introduce new bacteria into the vagina—some of which may be pathogenic. 

Having unprotected sex—especially with new or multiple partner(s)—can increase your chances of experiencing vaginal infections like BV.²¹ Since semen is slightly alkaline, having sex with a male partner can also alter the vaginal pH temporarily.⁷

If you use lube, that can also affect your vaginal microbiome temporarily. “Even clinical lubricants, like those used during routine vaginal exams, can affect the vaginal microbiota composition,” explains Mainieri.

7. Douching 

Vaginal douching (the practice of rinsing the vagina with water or other fluids) can disrupt the natural pH, increasing the chance of dysbiosis and putting you at higher risk of infections.⁷ Using soap of any kind on the vagina is not recommended, as it tends to be more alkaline than the ideal microbial environment.²² 

8. Smoking 

By this point, we all know smoking cigarettes isn’t good for you. But if you need yet another reason to quit, some research has linked smoking to a decrease in protective bacteria and a higher risk of BV.²³ 

Researchers are still trying to fully understand the relationship between smoking and BV risk, but one possible explanation is that cigarette smoking can have anti-estrogenic effects, which may negatively impact the growth of Lactobacillus species in the vagina.^24,25 

Another reason might be due to the presence of benzopyrene diol epoxide (BPDE), a chemical in cigarette smoke that has been found in the vaginal secretions of smokers. BPDE can change the DNA in lactobacilli, which might explain why cigarette smokers tend to have lower levels of lactobacilli in their vaginal microbiomes.²⁵ 

9. Your Diet 

“Your diet and alcohol intake may have an impact on the composition of your vaginal microbiome, potentially influencing your risk of developing a vaginal microbiota associated with BV,” says Mainieri. 

While the relationship between diet and the vaginal microbiome is complex and multifaceted, some studies have shown that eating lots of sugary, processed foods could lead to harmful bacteria growth, while a low-fat diet rich in fiber, fruits, veggies, and nuts and seeds (which are rich in phytoestrogens) could promote a more balanced microbiome.^26,13,27 

10. Sweat, Moisture, and Swimming

Yeast and bacteria need moisture to thrive, so the lingering sweat from a workout can cause microbes to multiply around the vulva.^28,29 The vulva forms the first line of defense against vaginal infection, so accumulated sweat in that region can result in VMB imbalance.²² Anecdotally, staying in a wet bathing suit after swimming might also trap bacteria, though this has never been scientifically studied. 

That said, a lack of physical activity is also a risk factor for vaginal infections, so this isn’t to say you should avoid exercise—just do your best to get out of those sweaty, wet clothes after.³⁰

Let’s Recap: How to Tend to Your Vaginal Microbiome “Garden” Daily

Now that we know how important the vaginal microbiome is and have a sense of its key disruptors, let’s dig into some ways to support yours daily:

• Use protection during sex: Condoms and dental dams can help reduce the risk of STIs and minimize disruptions to the vaginal microbiome.
• Eat a plant-rich diet: Incorporate a variety of fruits, vegetables, whole grains, nuts, and seeds into your diet to support microbial diversity in the gut, and to protect vaginal microbial balance. 
• Ditch the douche: Vaginal douching can disrupt the natural pH of the vagina, increasing the risk of dysbiosis and infections. Your vagina is a self-cleaning organ, so there’s really no need to douche. 
• Limit antibiotic use: Use antibiotics only when necessary and as prescribed by a healthcare provider to minimize disruption to the “good bugs” throughout your body.
• Quit smoking: Smoking can negatively impact the vaginal microbiome and increase susceptibility to infections.
• Limit exposure to harsh chemicals: Avoid using harsh or scented products in the vaginal area, as these can disrupt the harmony of the vaginal microbiome.
• Use a probiotic: Vaginal probiotics can also help colonize the VMB with beneficial bacteria. Look for one that uses clinically studied Lactobacillus strains and can be inserted directly into the vagina, as oral capsules seem to be less effective at delivering these protective microbes to the vagina.³¹ 
• Change out of sweaty, wet clothes quickly: Change into fresh, dry clothes after exercise to keep moisture-loving bacteria from forming in the vulva region.

The vaginal microbiome plays an essential role not only in day-to-day vaginal comfort, but also in disease risk, healthy pregnancies, and more.³² It exists in a constant state of change and you can nurture yours by implementing some of these daily practices. Think of them like watering, pruning, and fertilizing your vaginal landscape so it can flourish into a lush, harmonious garden.