how the human microbiome affects fertility in females and males

Right now, the hot thing in medicine is the human microbiome. Everywhere you look in the popular media you see discussions of the beneficial microbes (bacteria, yeast, etc.) that flourish in and on our body. In truth, this line of research is far from a passing fad having resulted from years and years of research in near obscurity.

We know that microbes flourish many places in our bodies—intestines, skin, nose, and vagina. The human body contains trillions (yes, that’s with a ‘t’) of microorganisms — outnumbering human cells by 10 to 1. This microbiome plays a vital role in our health, producing enzymes, vitamins, and anti-inflammatories that humans cannot produce on their own. It turns out that these little organisms also play an important role in our ability to reproduce.

Impact of Microbiome on Female Fertility

We recently did a fantastic interview on the Creating a Family Radio show with two of the leading researchers on how the microbiome impacts fertility. (see below) The short answer is that microorganisms are vital to getting pregnant and carrying a baby to full term.

Anyone who has ever had a yeast infection knows that the vagina has a rich microbial flora, and this microbiome aids or hinders the ability of the sperm to get to the egg. But it turns out that the vagina is not the only part of the female reproductive tract that has microbes that aid in conception.

It used to be believed that the uterus, fallopian tubes, ovaries, and surrounding areas of the upper female reproductive tract were a sterile environment, but recent research has proved otherwise. Bacteria, yeasts, and other microorganism flourish in these environments and are crucial in order to get and stay pregnant. A disruption of the balance in this microbiome may lead to infertility, miscarriage, or pre-term birth.

Even the placenta has a rich and varied microbiome. The placenta develops during pregnancy delivers food and oxygen to the growing fetus via the umbilical cord and removes waste products. The placenta is also important for the mother’s health influencing insulin resistance, preeclampsia, gestational hypertension, and even heart disease later in life. Research is now indicating that the placenta is also the source of the baby’s first microbes. What is further fascinating is that the microbiome of the placenta more closely resembles the microbiome of the mouth rather than that of the intestines or vagina. According to Dr. Jason Franasiak on the Creating a Family show, this finding points to the importance of oral hygiene during pregnancy.

How the Vaginal Microbiome Affects the Baby

The vaginal microbiome is crucial to the health of the baby once born, and changes during pregnancy to optimize the environment for birth. Researchers have found that the vaginal microbiome undergoes a dramatic shift in the type of bacterial species that are present as the pregnancy progresses.

“A newborn is a bacterial sponge as it populates its own microbiome after leaving the sterile womb; passage through the birth canal gives the baby its first dose of microbes, so it may not be surprising that the vaginal microbiome evolved to make it a healthy passage.”

I find this absolutely fascinating.

Impact of Microbiome on Male Fertility

Women are not the only ones with microorganisms in their reproductive tract that impact their fertility. Researchers are finding that the microbiome of the male genital tract, including in the semen, can impact his fertility.

Radio Show on Microbiome and Fertility

On the Creating a Family show on The Microbiome and Fertility, we interviewed Dr. Jason M. Franasiak, Associate Chair, Society for Reproductive Endocrinology and Infertility, Board Certified Reproductive Endocrinologist with RMA New Jersey; and Dr. Erin Wolff, former Assistant Clinical Investigator with the National Institute for Health and now Chief Medical Officer at Celmatix. These two are doing and have done some of the cutting edge research on how the microbiome affect fertility. We discussed what woman can do to improve their vaginal and reproductive tract microbiome, and perhaps more important, what does not work.


Other Creating a Family resources you will enjoy:

Image credit: American Society for Microbiology (fascinating organization and website if you are interested in learning more about the human microbiome)