Chronic endometritis is a persistent inflammatory condition affecting the endometrium, the tissue lining the inside of the uterus. Unlike acute endometritis, which involves a sudden and short-term infection, the chronic form is a lasting, low-grade inflammation that is often overlooked. It is important to distinguish chronic endometritis from endometriosis, a condition where tissue similar to the uterine lining grows outside the uterus.
Causes and Risk Factors
The development of chronic endometritis is primarily rooted in a persistent microbial presence within the uterine cavity. Bacteria that are normally found in the vagina can sometimes travel into the uterus, leading to a lasting infection and inflammation. Common bacteria implicated in this condition include Enterococcus faecalis, Escherichia coli, Streptococcus, and Staphylococcus.
Several factors can increase the likelihood of developing chronic endometritis by creating opportunities for bacteria to enter and colonize the uterus. The presence of an intrauterine device (IUD) for contraception is one such risk factor. Individuals who have recently undergone uterine procedures, such as a dilation and curettage (D&C) or hysteroscopy, or have experienced childbirth or a miscarriage, may be at higher risk.
In some instances, the condition is associated with retained products of conception, where small amounts of tissue remain in the uterus following a pregnancy or miscarriage. Pelvic inflammatory disease (PID), an infection of the female reproductive organs often stemming from sexually transmitted infections, is another recognized cause. The underlying connection in all these scenarios is the introduction and persistence of bacteria in an environment that is normally sterile.
Symptoms and Associated Conditions
The clinical presentation of chronic endometritis can be subtle, and a notable number of individuals with the condition are asymptomatic. When symptoms do occur, they are often non-specific and can include abnormal uterine bleeding, such as spotting between periods, persistent pelvic discomfort, and discomfort during intercourse. These symptoms can be easily attributed to other gynecological issues, which often leads to the condition being underdiagnosed.
A primary concern with chronic endometritis is its strong association with significant reproductive challenges. The condition is frequently identified in individuals experiencing infertility, recurrent pregnancy loss (RPL), and repeated implantation failure (RIF) during in vitro fertilization (IVF) cycles. It is believed that the persistent inflammation within the endometrium creates a hostile environment for an embryo, interfering with the uterine lining’s ability to become receptive to a fertilized egg.
The inflammation is thought to alter the local immune environment of the uterus. This includes changes in the populations of immune cells and the molecules they produce, which can disrupt the delicate signaling required for an embryo to attach and develop. For this reason, testing for chronic endometritis is often recommended for those who have experienced multiple failed IVF cycles or recurrent miscarriages without another clear cause.
The Diagnostic Process
Diagnosing chronic endometritis requires a direct evaluation of the uterine lining, as symptoms alone are not sufficient for a definitive conclusion. The diagnostic process typically begins with a procedure called hysteroscopy. During a hysteroscopy, a thin, lighted tube with a camera is inserted through the cervix into the uterus, allowing a physician to visually inspect the endometrial cavity for signs like redness, stromal edema, and micropolyps.
While hysteroscopy provides strong visual evidence, the conclusive diagnosis is made through a histological examination of an endometrial biopsy. A small sample of the uterine lining is analyzed for the definitive sign of chronic endometritis: the identification of plasma cells. To enhance the accuracy of identifying these cells, a specific laboratory technique called immunohistochemistry is employed. This method uses a CD138 stain and is considered the gold standard for confirming a diagnosis.
Treatment Approaches
The primary goal of treating chronic endometritis is to eliminate the underlying bacterial infection and resolve the inflammation of the uterine lining. The standard treatment is a course of oral antibiotics. Doxycycline is frequently prescribed as a first-line therapy, typically for a period of 14 days, although the choice of antibiotic may be tailored based on the specific bacteria identified.
Following the completion of the antibiotic regimen, it is important to confirm that the treatment has been successful. This is accomplished through a “test of cure,” which involves a follow-up endometrial biopsy. The new tissue sample is examined to ensure that the plasma cells and other signs of inflammation have been eradicated. If inflammation persists, a second or different course of antibiotics may be necessary.
Some healthcare providers may also recommend using probiotics, either orally or vaginally, after treatment. The aim is to help re-establish a healthy uterine microbiome, which may support endometrial health and reduce the risk of recurrence.