Why is vaginal microbiota important for fertility?

Female fertility encompasses a variety of biological, environmental, and even psychological factors, but the importance of the microbiota in the reproductive process is often ignored.

In basic terms, microbiota can be defined as the set of microorganisms that inhabit the human body. Recent studies demonstrate that managing and understanding the influence of these agents can play a decisive role in reproduction and assisted reproduction treatments .

This is the opinion of Cristian Hidalgo, founder of the Latin American Institute of Gynecology (ILAGINE), who specializes in treatments related to the female microbiota.

According to the specialist, bacteria of the Lactobacillus genus are some of the most prevalent and important beneficial organisms for reproductive health.

"These lactobacilli are like our police officers and are present in the vagina and also in the endometrium, which is where the baby will form. They produce various substances such as lactic acid, hydrogen peroxide, and other cytotoxins that promote the normal development of the entire urogynecological system," explains Hidalgo.

The U.S. National Center for Biotechnology Information notes that a healthy vaginal microbiota is primarily composed of resident Lactobacillus species such as L. crispatus , L. iners , L. jensenii , and L. gasseri . These organisms act as probiotics and inhibit the overgrowth of other bacterial species through various mechanisms, including the aforementioned cytotoxins.

"If lactobacilli levels are good, the vagina, uterus, fallopian tubes, and ovaries will function well. When these microorganisms are lost, various germs from the skin, intestines, and those transmitted through sexual intercourse can enter the vagina. Without the protection of lactobacilli , they begin to reach the uterine cavity and begin to cause fertility problems," the gynecologist adds.

The specialist indicates that in studies carried out on women undergoing in vitro fertilization treatments, those who were in the 60% of successful embryo implantation cases were those who had acceptable levels of vaginal flora , while the 40% who were not successful had the presence of other types of external bacteria that took the place of the regular beneficial microbiota.

"This way, it was determined that lactobacillus plays a very important role in fertility and the development of pregnancy. It has also been found that in patients who experience recurrent miscarriages, these lactobacillus levels have decreased , and there are other types of germs that generate an entire inflammatory process," says Dr. Hidalgo.

Once pregnancy has begun in the strict sense, beneficial microorganisms remain important, as they contribute to the prevention of infections during pregnancy.

The microbiota develops over many years, and its development begins even during pregnancy, according to Cristian Hidalgo, who maintains that the factors that influence its development are diverse: whether the expectant mother was born by normal delivery or Caesarean section, and whether she was breastfed.

Infants who were born naturally and breastfed tend to have higher levels of beneficial microbiota than those who did not undergo this process.

Additionally, a relevant factor is nutrition.

“Refined sugar, gluten, sweet fruits, and dairy products all have high glucose levels, which favors the growth of microorganisms other than lactobacillus,” comments ILAGINE's CEO.

Also relevant to microbiota regulation are prolonged stress levels, the use of antibiotics, antacids, and corticosteroids . Also relevant to female reproductive flora, although to a lesser extent, are hygiene and the use of certain intimate hygiene products, as well as sexual practices.

"Of all these factors (of influence) that we have observed over the years, the main ones are diet and chronic stress," says Hidalgo, who recommends eating vegetables, foods rich in fiber, and including probiotics.