What is chronic endometritis?
Chronic endometritis is a localized and persistent inflammatory alteration in the endometrium (the inner lining of the uterus), characterized by the infiltration of plasma cells (cells of the immune system).
In the field of fertility and assisted reproduction, it has been proposed that this silent and almost always asymptomatic inflammation could be the cause of good quality embryos failing to implant in the uterus, that is, as a factor that could contribute to recurrent implantation failure.
The "myth" of implantation failure
Recent scientific data offer a much more reassuring perspective. True recurrent implantation failure, defined as repeated failure after the transfer of euploid embryos (with a normal chromosomal complement), affects only a small percentage of patients, specifically between 2% and 5%.
Current clinical data on euploid embryo transfers (genetically analyzed) demonstrate that cumulative implantation rates are high:
-
- 1nd transfer: 55-65%.
- 2nd transfer: 80-85%.
- 3rd transfer: ~90%.
- 4th and 5th transfer: ~95% and ~98% respectively.
Furthermore, comparative studies suggest that the prevalence of chronic endometritis in women with recurrent implantation failure is no higher than in control populations. These findings indicate that the actual impact of chronic endometritis on implantation failure may be much smaller than previously assumed.
Difficulties in diagnosis
Accurately diagnosing this condition remains a significant medical challenge. Currently, its diagnosis is problematic due to the lack of standardized thresholds, the wide variability in the timing of biopsies within the menstrual cycle, and the inconsistency in histological interpretation.
All of this can lead to frequent overdiagnosis of patients with endometritis.
The risk of using antibiotics
Given this diagnostic uncertainty, antibiotic treatments are frequently prescribed without confirming the presence of the causative pathogens. This routine practice raises serious medical concerns. Evidence regarding their therapeutic benefit is very limited and inconsistent, increasing the risk of overdiagnosis and overtreatment, and fostering the dreaded antibiotic resistance due to unnecessary exposure.
In short, the scientific community argues that routine evaluation of this condition is not generally recommended and that a selective and cautious clinical approach should be followed.
Original article by: Silvia Azaña Gutiérrez | www.reproduccionasistida.org | July 15, 2026
