According to a recent JBRA Assisted Reproduction study that looked at ART results, certain microbial profiles were linked to higher chances of conception.

The current study investigated the relationship between the quantity of Lactobacillus and the balance of pathogenic bacteria, including Gardnerella, Enterococcus, Enterobacteriaceae, Streptococcus, and Staphylococcus.

The researchers created a prospective study based on vaginal and endometrial microbiota samples from 35 ART patients who received embryo transfers at a single facility between February 2019 and March 2020. The study comprised a total of 34 vaginal samples and 33 endometrial samples, respectively.

The results showed that 21 of the 34 embryo transfer (ET) procedures led to pregnancy, with 17 live births and four preterm miscarriages. Most factors, including antibiotic use, were the same for pregnant patients as for the others. Both vaginal and endometrial samples from pregnant women included higher levels of Lactobacillus than those from non-pregnant women, with higher levels of Pathogenic Bacteria (PB).

High Lactobacillus (L)/low PB groups had higher rates of pregnancies, whereas low L/high PB groups had higher rates of pregnancies in non-pregnant women. Accordingly, a higher percentage of women who successfully became pregnant were associated with a favorable Lactobacillus-pathogenic bacterial balance in the endometrium and vagina. This held true even after individuals who received antibiotics were excluded. Diversity analysis, which validated these findings,

Endometrial receptivity to the implanting blastocyst is impacted by infection-induced inflammation when PB is plentiful. Furthermore, bacterial invasion of the endometrium may impair immunological tolerance, leading to blastocyst rejection.

These results suggest that Lactobacillus predominates in the vaginal and endometrial microbiomes and inhibits pathogenic bacteria entry into the uterus. More research is required to understand how the endometrial microbiota influences blastocyst implantation.

(Source: https://www.news-medical.net/news/20221209/Microbiomes-in-female-reproductive-tract-linked-to-pregnancy-following-use-of-ART.aspx)