Chronic endometritis may be a factor directly related to implantation failure and repeat miscarriages. Chronic endometritis involves symptomless inflammation of the endometrium, and its effect on fertility is controversial. In fact, it is possible that chronic endometritis reduces endometrial receptivity.
Some of these studies indicate that chronic endometritis can be diagnosed in up to three out of ten patients with implantation failure, and others detect it in up to six out of ten women with repeated miscarriages. However, some authors argue that, as a symptomless condition, chronic endometritis may be present in patients who have a normal implantation rate.
Chronic endometritis in implantation failures
In 2018, a meta-analysis on the role of chronic endometritis in implantation failures was performed, indicates that we are still far from being able to draw conclusions. However, it is suggested that having information about possible chronic endometritis, using an appropriate antibiotic treatment and, finally, confirming through a second endometrial biopsy that the endometritis has healed, before starting another IVF cycle, could lead to improved outcomes, giving these patients a chance of pregnancy similar to that of the group of patients without chronic endometritis.
The meta-analysis has included studies in which the definition of implantation failure was two or three IVF cycles (with frozen or fresh embryos) in which at least one embryo (in cells or blastocyst) of good quality was transferred in each of the cycles. Chronic endometritis in these studies has been defined by the presence of plasma cells in an endometrial biopsy or by immunohistochemistry.
The authors insist on the importance of confirming with an endometrial biopsy that the patients who have been treated with antibiotics have eliminated the chronic endometritis, since otherwise no improvement is observed in comparison with those who have not undergone treatment.
The patients with chronic endometritis resolved, obtained a significant improvement in the probability of implantation, pregnancy rate, evolutionary pregnancy and child born. The results obtained were similar to those of patients without endometritis, showing the importance of treatment. However, there was no improvement in the risk of miscarriage.
Chronic endometritis in recurrent miscarriages
Recent studies and research have confirmed an improvement in the prognosis of evolutionary pregnancy with repeat miscarriages after antibiotic treatment, if chronic endometritis is present.
Cicinelli (2014) defines repeat miscarriages as three or more miscarriages before 20 weeks of gestation, and it is considered to affect 3% of all couples. In some, genetic abnormalities, antiphospholipid syndrome, endocrine and other uterine abnormalities are even detected, although in other couples no specific problems have been detected.
Cicinelli retrospectively reviewed 360 cases of repeat miscarriage in which he performed diagnostic hysteroscopy. They argue that the presence of specific signs at hysteroscopy, such as micro-polyps, stromal edema or focal or diffuse hyperthermia, reliably diagnose chronic endometritis, and they detected these problems in 57% of patients with repeated miscarriages.
In addition, histological confirmation of endometritis was found in 91%, and a positive culture in 68% of them. The majority of contamination (77%) was due to common bacteria, and less frequent were those caused by mycroplasma or ureaplasma (25%) and chlamydia (12%).
The patients who suffered from chronic endometritis – by culture or histology – managed to normalize their endometrium after appropriate antibiotic treatment, were 59%. Most of these patients achieved an evolutionary pregnancy after one year (75%). The improvement was somewhat higher in patients with positive cultures compared to those with histological signs of chronic endometritis.
It is possible that cultures fail to detect all the infectious agents that cause endometritis, so antibiotic treatment is not fully effective in this group of women.
In conclusion, in patients with implantation failure or repeated miscarriages, endometrial biopsy may be of interest. Endometrial biopsy is a simple test that also allows an immunohistochemical study and culture to detect possible chronic endometritis, which if treated could improve endometrial receptivity to the embryo.
For more information about the relationship between chronic endometritis and infertility, we offer a free initial consultation. You can make an appointment at UHR GarcÃa del Real or with a specialist in Assisted Reproduction.