Multiple uterine factors are thought to affect the success of an IVF cycle including endometrial polyps, fibroid tumors in the uterus, scar tissue in the uterus, and possibly a subtle infection in the endometrial tissue that produces no symptoms (chronic endometritis). These infections are hard to detect by doctors and are thought to be present in only a very small percentage of otherwise asymptomatic women undergoing IVF. Usually, an endometrial biopsy is used to make the diagnosis looking for special cells called plasma cells in the endometrium. Several factors make the identification of plasma cells difficult to detect. Only a few studies have been done in the past looking at the effect of chronic endometritis on fertility. These studies did not show a clear relationship between endometritis and reproductive outcomes.
A study reported in Fertility and Sterility in 2011 from the Netherlands looked at endometrial tissue samples from over 600 women and found that 2.8% (17 women) showed chronic endometritis. The investigators then compared these 17 women to 68 randomly selected women undergoing IVF who were similar to those with endometritis. When the live birth rate was studied, the patients with endometritis had a higher pregnancy rate (76%) when compared to the randomly selected group (54%). However, this difference was not statistically meaningful in terms of IVF success.
Doctors rarely find the cause of chronic endometritis using culture techniques. Bacteria are rarely found. The cause of chronic endometritis remains uncertain. Based on this study and previously published reports, chronic endometritis has no proven association with infertility. Moreover, the effect of antibiotic treatment on nonspecific chronic endometrial inflammation is disputable. Routine endometrial biopsy to detect chronic endometritis therefore should not be recommended for daily clinical practice.