The Vaginal Microbiome and Fertility

Did you know that the bacteria *down there* can help or hinder conception? That’s right, your vagina and endometrium have a microbiome (similar to your gut) that plays a role in implantation of an embryo (particularly in IVF).

Good vs. Bad Bacteria  

We’ve known for a while that infections like chlamydia, gonorrhea, E.coli and other pathogenic bacteria are associated with impaired fertility.

But now we know that having the wrong composition of ‘normal’ vaginal bacteria ALSO impairs fertility. 

Lactobacillus are the most abundant bacterial species found in the female reproductive tract. Fertility researchers have defined a composition ≥ 90% lactobacillus species as a lactobacillus dominant microbiome and < 90% as a non-lactobacillus dominant microbiome. This is a statistically significant differentiation that helps us predict reproductive success (particularly IVF).

Lactobacillus and Infertility

A non-lactobacillus-dominated microbiota (< 90%) is significantly correlation with adverse pregnancy outcomes like poor implantation, early loss of pregnancy and lower live birth rates. A recent study found that 32/34 women with a non-lactobacillus-dominated microbiota had unsuccessful embryo transfers.

A Lactobacillus dominant vaginal microbiota (≥ 90%) is correlated with positive reproductive outcomes! Women with >90% lactobacillus have a higher success rate in both full-term pregnancy and live birth rates!! 

When I’m working with couples undergoing IVF, we do everything in our power to improve their chances of success - this is another amazing tool to achieve that healthy pregnancy and baby.

Benefits Beyond Fertility

A Lactobacillus dominant vaginal microbiome is critical for sexual health. Lactobacillus protects against infections and maintains a healthy vaginal epithelium. This is primarily through the production of lactic acid, which creates a low-pH vaginal environment unsuitable for pathogenic bacterial growth. Low Lactobacillus spp. is a risk factor for recurrent bacterial vaginosis (which thrives in less acidic environments). 

An altered vaginal microbiome also puts you at a higher risk for yeast infections (Candida spp.). We know that Lactobacillus levels decrease as hormonal levels do (particularly progesterone). We see this clinically in women on hormonal contraceptives and in the days leading up to mensuration. Interestingly, yeast infections commonly present in the late luteal phase, just before your period when your hormones and lactobacillus spp. are both at their lowest!

Maintaining a healthy vaginal microbiome is critical for infection prevention, vaginal health and reproductive outcomes. If you currently get frequent or recurrent vaginal bacterial or yeast infections it may be time to take care of your vaginal microbiome.