Fact Check: Can Probiotics Increase Fertility?

From prenatal vitamins to “hormone-balancing” supplements, there’s no shortage of options claiming to support conception. But one supplement that’s starting to get more attention? Probiotics.

That’s because more research is pointing to the importance of a lesser-known (but incredibly important) factor in reproductive health: your vaginal microbiome. Research continues to show that the vaginal microbiome plays a key role in pregnancy outcomes, so it’s only natural to wonder whether probiotics should be part of your fertility supplement routine. 

While probiotics aren’t a magic fix, they may play a valuable role in supporting the vaginal environment that’s essential for fertility. Let’s break down what we know so far, what probiotics have to do with it, and how you can better understand your body during your fertility journey.

Can probiotics help with fertility?

Short answer: Potentially, but it's not that simple. There’s emerging — but not definitive — evidence that probiotics may help with fertility, especially in cases like unexplained infertility (infertility with no known cause).

The vaginal microbiome (the community of bacteria that lives in the vagina) plays a crucial role in reproductive health. A microbiome dominated by beneficial bacteria like Lactobacillus species is generally considered protective because the presence of Lactobacillus in the vaginal microbiome helps maintain an acidic environment that inhibits the growth of pathogenic organisms. Imbalances (dysbiosis), on the other hand, have been linked to lower chances of conception, higher risk of miscarriage, and poor outcomes with in vitro fertilization (IVF). 

Some research suggests that certain probiotic supplements may help restore or maintain a healthier, Lactobacillus-dominant vaginal environment. Probiotics may support fertility in several ways. A balanced vaginal microbiota is protective against vaginal infections like bacterial vaginosis (BV), which has been linked to infertility, miscarriage, and reduced IVF success. Additionally, probiotics may help reduce inflammation in both the gut and reproductive tract, which could improve the chances of implantation success. There’s also emerging evidence suggesting that a healthy vaginal and gut microbiome affects estrogen levels, further linking microbial health with reproductive function.

The theory is that by improving vaginal microbiota, probiotics could indirectly increase the likelihood of a successful pregnancy. But while the idea is promising, current evidence is either mixed or too limited to support probiotics as a proven fertility-boosting intervention, at least for now.

One study found that oral supplementation with a specific strain, Ligilactobacillus salivarius CECT5713, improved term pregnancy rates in women undergoing IVF treatment. The researchers also observed better immunological markers, even though there weren’t dramatic changes in vaginal microbiota composition. 

Other studies have shown that probiotics, especially those with Lactobacilli, may help balance the bacteria in the vagina, potentially supporting the health of the reproductive system. Another study reported that women receiving Lactobacillus supplementation reported a lower miscarriage rate compared to those who did not receive it.

But here’s the catch: results vary widely depending on the probiotic strain, dose, and how it's taken. Not to mention, clinical trials have used different patient populations with different causes of infertility, which makes the results hard to compare. This means that the scientific and medical community has not yet come to an overall consensus about which probiotic treatment should be given to which group of people. 

Another area of research is polycystic ovary syndrome (PCOS). Some preliminary studies suggest that probiotics might help manage PCOS by improving gut and reproductive tract microbiota, as well as influencing metabolic and hormonal balance. That could be meaningful for fertility outcomes, but again, we’re in the early stages, and more high-quality studies are needed to know for sure.

Best probiotics for female fertility

Current evidence suggests that certain probiotic strains may have a beneficial effect on female fertility, particularly in women with unexplained infertility or those undergoing assisted reproductive technologies like IVF. Here are the strains that science is paying the most attention to:

• Ligilactobacillus salivarius CECT5713: This is the standout so far. A randomized, triple-blind, placebo-controlled trial found that women with unexplained infertility who took this strain had significantly higher term pregnancy rates before IVF — 48.1% vs. 20.0% in the placebo group. That's a pretty compelling difference.
• Ligilactobacillus salivarius PS11610: This strain has also shown promising results in restoring healthy vaginal microbiome balance and improving both pregnancy and delivery rates in couples facing unexplained infertility.
• Ligilactobacillus salivarius CECT 30632: This strain has been associated with better pregnancy outcomes in women dealing with recurrent miscarriage or unexplained infertility, likely by helping modulate the vaginal immune environment to be more supportive of conception.
• Vaginal Lactobacilli: Strains like Lactobacillus rhamnosus (GR-1 and HN001), Lactobacillus reuteri (RC-14), and Lactobacillus crispatus have been shown to help shift the vaginal microbiota toward a healthier, Lactobacilli-dominant state, which is generally linked with better reproductive outcomes.
• Other probiotic strains for PCOS: Some research has explored strains like Bifidobacterium and various lactic acid bacteria to help with the gut microbiome and PCOS-related infertility. These may influence hormonal balance and metabolic health, but the evidence for specific strains is still emerging and less robust compared to the others mentioned.

Should you take a probiotic for fertility?

Right now, medical guidelines don’t recommend probiotics as a standard fertility treatment. But that doesn’t mean they’re not a helpful tool, especially if you’re looking to support your vaginal microbiome, which is definitely worth paying attention to when you’re trying to conceive. Think of it as one piece of the fertility wellness puzzle: it might not be the magic bullet, but it can support a foundation of reproductive health.

It's important to keep our expectations realistic. While having a Lactobacillus-dominant microbiome is linked to better fertility outcomes, there isn’t a ton of solid evidence showing that probiotics can directly boost pregnancy rates just yet. Most studies suggest they help get things back on track after issues like dysbiosis, infections, or antibiotics, rather than being a sure-fire way to enhance fertility. Taking a targeted probiotic, like Evvy Women's Complete Probiotic, can support a more balanced vaginal environment regardless of whether you’re trying to conceive or not. 

As with any supplement, probiotics should be considered part of a holistic approach to fertility that includes nutrition, lifestyle, and medical care. And of course, it’s always best to consult a healthcare provider before starting a new supplement, especially if you’re dealing with underlying health issues or undergoing fertility treatments.

Get to know your microbiome

Want to know what’s really going on in your vaginal microbiome? Start with the Evvy Vaginal Health Test, which gives you personalized insights into the makeup of your vaginal microbiome — information that standard fertility tests often miss. By understanding whether your microbiome is balanced or showing signs of dysbiosis, you can uncover potential barriers to conception and make more informed decisions about how to support your reproductive health. 

FAQ

What probiotics help you get pregnant?

Some probiotic strains, like Lactobacillus rhamnosus, Lactobacillus reuteri, and Lactobacillus crispatus, have been linked to better vaginal health, which may support fertility by promoting a balanced microbiome. A healthy vaginal environment can reduce infections and inflammation that interfere with conception. While emerging research is promising, especially in cases of dysbiosis or unexplained infertility, probiotics aren’t currently recommended as part of official guidelines if you’re trying to conceive. They may be a helpful tool in a broader reproductive health strategy, but more evidence is needed to confirm their direct impact on pregnancy rates. Always consult your doctor before starting a new supplement.

Can probiotics increase fertility?

Probiotics may support vaginal health, but there’s no strong evidence yet that they directly increase fertility. Certain strains — especially Lactobacilli — can help promote a healthy vaginal microbiome, which is important because imbalances like bacterial vaginosis are linked to infertility, miscarriage, and poor IVF outcomes. Some early studies have shown promising results in specific groups, such as women with unexplained infertility, but the data is still limited and inconsistent. So while probiotics may indirectly support fertility by improving gut and vaginal health, they are not a guaranteed fertility booster and are not part of official fertility treatment guidelines for the time being.