top of page

Probiotics WHERE?! What You Should Know About Fertility and the Vaginal Microbiome

Updated: May 12, 2020

Newsflash: there's a massive ecosystem teeming with millions of life forms, living right inside...your vagina.

Introducing...The Vaginal Microbiome

You’ve probably heard of the microbiome in your digestive tract, which plays a role in fine-tuning your immune system and controlling inflammation in your body that can contribute to anything from diabetes to neurodegenerative diseases.

But who knew that the vagina has one too?! Nobody told us.

And, just like in your digestive tract, this one is FILLED with beneficial bacteria and other microorganisms. Or so you hope...

Your VM is Sensitive to Imbalances

The problem is - the bacteria aren’t always in an optimal balance.

"Significant numbers of healthy women lack appreciable numbers of vaginal lactobacilli." - Professor R.F. Lamont, National Institute of Child Health and Human Development, NIH/DHHS, Bethesda

Over 1 BILLION women each year around the world suffer through infections and changes to their vaginal microbiota that lead to disease. Researchers say this not only compromises our wellbeing and day-to-day lives, BUT can also affect our reproductive health -- which is why it’s a great idea to understand more about this bacteria colony in your nether regions so you can help it thrive.

Get this: scientists say that at any given time, nearly one-third of American women of reproductive age have something called bacterial vaginosis (BV). This is a fancy name for what basically means an imbalance of bacteria in your vagina. Specifically, BV is caused by a lack of the most common GOOD bacteria in the vagina -- a strain called Lactobacillus - plus an overgrowth of some other microbes.

This imbalance can mean all kinds of really annoying and uncomfortable things like a fishy or other unwelcome odor, discharge, discomfort, itching and swelling.

How BV Affects Fertility

There’s no direct research to say what impact an infection or imbalance of bacteria could have on your maturing eggs, but scientists do think the microbiome plays an important role in reproductive health.

Recently, studies have linked specific vaginal microbes and infections with preterm birth and with pelvic inflammatory disease (which can lead to infertility).

And given the links with inflammation and egg quality -- it’s a good idea for your egg freezing cycle to try to start with the optimal balance.

Women with BV also have a higher risk of miscarriage, contracting sexually transmitted infections, acquiring and transmitting HIV, and other vaginal and uterine infections like trichomoniasis.

A study on sex workers in Thailand showed that those with BV were four times as likely to be HIV positive as those without BV. Researchers think this might be because bad bacteria can alter vaginal mucus (or more specifically, their enzymes can hamper an antibody component linked to immune response) which leaves women vulnerable to infection.

It’s now even thought that exactly which KIND of Lactobacillus species a woman has in her vagina might mean the difference between HIV infection and protection. Research shows that sex workers in Rwanda with L. crispatus as the dominant bacteria in their vaginas were less likely to have HIV and other STIs. So, if you remember, that’s the kind that was most commonly found in white women, which was thought to give some protection against BV.

L. crispatus might be the top dog of the bacteria world because it keeps the vagina at a low - or, acidic pH by pumping out lactic acid that makes other bacteria, yeast and viruses back off.

Some Women Run a Higher Risk of Imbalance

The research is still pretty sparse, but studies show that some women are more likely to struggle with imbalances in the vaginal microbiome that lead to things like BV than others.

  • If you’re African American or Mexican American - you’re more likely to be affected than Caucasian women. In a study, 23% of white women were positive for BV, compared with nearly one-third of Mexican American women and over half of African American women. Some researchers point to the fact that for each ethnic group, there’s one bacterial community that is by far the most common. In studies, Asian women’s vaginas have been dominated by L. iners. For white women, it's L. crispatus. Meanwhile, black and Hispanic women have pretty diverse microbiota, which could potentially explain why they have higher rates of BV. Basically: it's thought some Lactobacilli strains are more protective than others.

  • If you use scented sprays, soaps and wipes on your vulva and vagina - In one study, women who used gel sanitizers — whether externally of internally — were 8 times more likely to have a yeast infection and almost 20 times more likely to have reported bacterial vaginosis. Women using feminine washes were almost 3.5 times more likely to have reported a bacterial infection and 2.5 times more likely to have had a UTI. Feminine wipes were also associated with double the risks of a UTI.

  • If you douche - Douching may remove normal vaginal flora, permitting the overgrowth of pathogens.

  • If you have a new sexual partner or multiple sexual partners (without using a condom) --- although somewhat surprisingly, in studies bacterial vaginosis (BV) was present in 15%t of women who reported never having had sex.

  • If you're NOT on the contraceptive pill - there is actually a reduced risk of bacterial vaginosis if you take oral contraceptives. The effects of sex hormones on the vaginal microbiota are not entirely known, but estrogen seems to play an important role in promoting the growth of lactobacilli. Postmenopausal women not on hormone therapy have been found to have lower levels and diversity of Lactobacillus compared with those who use hormone therapy.

What Can you Do About It?

If you already have BV, antibiotics remain the recommended (and the only FDA approved) treatment for BV. The trouble is: antibiotics are not exactly sharp-shooters. Current cure rates from the recommended antibiotic, metronidazole, run at around 50–80% but it's really common for BV to come back. Actually, around half of the millions of women who get BV get it RECURRENTLY.

Some researchers think that antibiotic treatment can actually make the situation worse. That's because antibiotics kill off not only the bad bacteria but also the beneficial bacteria in the microbiome, which...can actually lead to MORE imbalance. This is why taking antibiotics can be linked to thrush.

Thrush - as you may already know INTIMATELY - is a vaginal yeast infection that also stems from an imbalance in the vagina. But in this case, the problem is a fungus called Candida. This fungus exists normally in the vagina without causing any problems, BUT it may start to cause that ole’ itch and scratch if it starts to outnumber other know, let’s say if a round of antibiotics just killed them all off...

Can you Prevent Imbalances?

If an abundance of Lactobacillus bacteria found in your vaginal microbiome is associated with good vaginal health, should we all be taking it as a probiotic in pill form?

Well, maybe.

Some research is positive and suggests that taking a daily probiotic capsule can be effective in preventing and treating vaginal imbalance, but the datasets are small.

One problem seems to be getting the good bacteria to hang around in vagina. Suppositories have been shown to cure BV and also maintain a healthy balance of vaginal bacteria following treatment, but, just...not for very long.

Eating plenty of Lactobacillus rich food might be better. Data shows that women who ate probiotic yogurt containing Lactobacillus had a larger amount of Lactobacillus bacteria in their vaginas than those who did not AND they were less likely to experience BV.

Another thing to look at is reducing your sugar intake (if you’re not already!). Women with high blood sugar are more susceptible to contracting yeast infections. And try to eat plenty of what are called “prebiotics” like fresh fruits, vegetables, and whole grains that help promote growth of healthy bacteria.

If you ARE interested in the suppositories (capsules inserted into the vagina), they are available over the counter in Europe. And in the US, there’s a promising clinical trial of an L.crispatus probiotic suppository called LACTIN-V.

In Summary

More research is needed to definitively determine whether or not probiotics are an appropriate treatment for vaginal imbalance issues - the studies we have a small and limited at the moment, so it’s hard to say for sure what the right move is.

There’s not conclusive evidence showing that probiotics are effective at preventing and treating BV or other imbalances BUT some evidence does show that probiotics in yogurt, capsules, and vaginal suppositories may help prevent and treat imbalance in the vagina. It’s's unclear how effective they are at actually colonizing the vagina over a period of time.

Looking at different combinations and strains of probiotics to help restore optimal balance in the vagina is presently an active area of research, so watch this space.

There are no known risks to taking a probiotic, although to be clear - it’s really unknown. Introducing any bacteria...even good ones...could have unintended consequences, so weigh everything up in your own mind and check with your doctor before using anything.

One piece of food for thought that really illustrates how little we still know about probiotics as a whole were the results of a study that found that when people were given a probiotic after antibiotic treatment, their natural gut bacteria actually took longer to recover than the gut bacteria of people who didn't take the probiotic. That’s something to think about, for sure.

And just bear in mind that as with any supplement - "caveat emptor" or: buyer beware.

Like any supplement, probiotics are not FDA regulated as things stand. Trust the brand. Research the ingredients.

Or maybe just stick to the yogurt...


Read the full story

If you want to learn more about the vaginal microbiome and how it might impact your fertility treatment outcome, a full review can be found in the book Everything Egg Freezing: the Essential Step-by-Step Guide to Doing it Right.



The vaginal microbiome: new information about genital tract flora using molecular based techniques.

Vaginal Microbiome and Its Relationship to Behavior, Sexual Health, and Sexually Transmitted Diseases.

A delicate balance: risk factors for acquisition of bacterial vaginosis include sexual activity, absence of hydrogen peroxide-producing lactobacilli, black race, and positive herpes simplex virus type 2 serology.

Bacterial vaginosis and risk of pelvic inflammatory disease.

First Trimester Levels of BV-Associated Bacteria and Risk of Miscarriage Among Women Early in Pregnancy.

Menopause and the vaginal microbiome.

Bacterial vaginosis: resistance, recurrence, and/or reinfection?

Making inroads into improving treatment of bacterial vaginosis - striving for long-term cure.


bottom of page