Where did the year go? Hope everyone had a great thanksgiving and looking forward to the Christmas season.
I gave a virtual postgraduate course at this year’s ASRM conference in Baltimore discussing Chronic Endometritis and it’s association with recurrent pregnancy loss. Here is a brief summary of the important points and some bottom lines.
What is chronic endometritis?
It is a persistent inflammation of the endometrial lining.
How do we diagnose it?
There are several ways, one is taking a sampling of the lining of the uterus called an endometrial biopsy. The sample will be sent to look for inflammatory cells called plasma cells by looking at the tissue and/or using a special staining for a marker on the surface of plasma cells, CD138 which highlights the plasma cells in the specimen making it easier to see them. See below this photo is taken from a publication from Mc Queen et al 2015 (McQueen, D. B., C. O. Perfetto, F. K. Hazard and R. B. Lathi (2015). "Pregnancy outcomes in women with chronic endometritis and recurrent pregnancy loss." Fertil Steril 104(4): 927-931.) On the left panel shows the different cells in the endometrium without CD138 staining and on the right panel shows the CD138 positive cells highlighted by the brown staining which are plasma cells. Experts have not agreed on how many plasma makes a diagnosis for chronic endometritis.
Other ways of making the diagnosis is looking directly inside the uterus using a camera called a hysteroscope. Features that are suggestive are micropolyps which are small outgrowths in the lining of the uterus. Again there is no consensus on what features are needed to diagnose chronic endometritis. Experts think that chronic endometritis is likely due to an imbalance of bacteria in the endometrium.
Chronic endometritis and link to recurrent pregnancy loss -
it is thought that chronic endometritis leads to alterations in the receptivity of the endometrium thus impacting the sticking of the embryo to the uterus therefore predisposing to miscarriage. Many studies have shown that chronic endometritis is found more commonly in women with recurrent pregnancy loss about 29% of women with recurrent pregnancy loss could have chronic endometritis.
Does treating chronic endometritis reduce miscarriage? -
This is the question you care about. Antibiotic therapy is the treatment for chronic endometritis. Several small studies have showed encouraging results by showing positive trend towards increase livebirth rates however a limitation of these studies is all women received antibiotics so there was no control group i.e. women who did not get antibiotics. More recently a study by Gay et al., (Gay, C., N. Hamdaoui, V. Pauly, M. C. Rojat Habib, A. Djemli, M. Carmassi, C. Chau and F. Bretelle (2021). "Impact of antibiotic treatment for chronic endometritis on unexplained recurrent pregnancy loss." J Gynecol Obstet Hum Reprod 50(5): 102034) compared the livebirth rate and miscarriage rate of 13 women with chronic endometritis treated with antibiotics and 9 women without antibiotics retrospectively. The livebirth rate of the women with antibiotics was 85% versus 44% in women without treatment. The miscarriage rate was significantly reduced in women treated with antibiotics 15% versus 56% in untreated women. Though this study shows very promising results, larger studies are needed to provide a definitive answer.
In the meantime, I test and treat chronic endometritis in my recurrent pregnancy loss patients given the treatment is relatively simple and the potential for significant benefit to my patients.