What is endometriosis?

The endometrium is the tissue that lines the inside of the uterine cavity. Endometriosis is a disease state in which some of this tissue has spread elsewhere – such as to the ovaries, or elsewhere in the abdominal cavity. Endometriosis causes pain in some women and can also cause infertility. 5-10% of all women have endometriosis. Most of these women are not infertile. 30-40% of infertile women have endometriosis.

Ovulatory disorders, tubal obstruction, and semen abnormalities are relatively easy to diagnose and account for the cause of infertility in approximately 75 percent of couples . When couples with these abnormalities are excluded, infertility in the other 25 percent of couples is usually due to endometriosis, which may be present in 40 percent of the female partners of these couples. The remaining cases are classified as unexplained infertility . Although endometriosis impairs fertility, it does not usually completely prevent conception. A combination of surgery, ovulation induction plus intrauterine insemination, and in vitro fertilization can be used to help these women conceive.

How does endometriosis affect fertility?

Mechanisms of infertility associated with endometriosis are controversial and likely depend, in part, on the stage of disease. The spectrum of disease ranges from minimal presence of ectopic tissue (eg, 1 to 5 mm implants on the pelvic peritoneum) to severe anatomic distortion (deep ovarian endometriomas, major pelvic adhesions with obliteration of normal pelvic organ relationships). Diagnosis of endometriosis The only way to be sure whether a woman has endometriosis is to perform a surgical procedure called laparoscopy that allows us look inside the abdominal cavity with a narrow scope. Sometimes we strongly suspect that the disease is present based on the woman’s history of very painful menstrual cycles, painful intercourse, etc., or based on the physical examination of the woman or ultrasound findings. The large majority of cases of endometriosis are mild. Women with any stage of endometriosis (mild, moderate, or severe) can have severe lower abdominal and pelvic pain – or they might have no pain or symptoms whatsoever.

Although mild endometriosis is associated with infertility in some women, many fertile women also have mild endometriosis. A cause and effect relationship between mild endometriosis and infertility has not been established. It might be that infertility and delayed pregnancy predisposes women to developing endometriosis, rather than the endometriosis causing the infertility. Therefore, some experts consider infertility associated with mild endometriosis to really be “unexplained infertility”.

Severe endometriosis Severe endometriosis causes pelvic scarring and distortion of pelvic anatomy. The tubes can become damaged or blocked and the ovaries often contain cysts of endometriosis (endometriomas) and may become adherent to the uterus, bowel or pelvic side wall. Any of these anatomic distortions can result in infertility. In some cases the eggs in the ovaries can be damaged, resulting in decreased ovarian reserve and reduced egg quantity and quality.

Treatment of endometriosis Treatment for endometriosis associated with infertility needs to be individualized for each woman. There are no easy answers, and treatment decisions depend on factors such as the severity of the disease and its location in the pelvis, the age of the woman, length of infertility, and the presence of pain or other symptoms. For treatment of the infertility associated with mild to moderate endometriosis, controlled ovarian hyperstimulation with intrauterine insemination – IUI is often attempted and has a reasonable chance to result in pregnancy if other infertility factors are not present.

If IUI is not successful by about 3 cycles, in vitro fertilization should be considered. Treatment for severe endometriosis Several studies have shown that medical treatment for severe endometriosis does not improve pregnancy rates for infertile women. Some studies have shown that surgical treatment of severe endometriosis does improve the chances for pregnancy as compared to no treatment.

However, pregnancy rates remain low after surgery – some studies have reported pregnancy rates of 1.5-2% per month. Unfortunately, the infertility in women with severe endometriosis is usually resistant to treatment with ovarian stimulation plus intrauterine insemination. If the pelvic anatomy is very distorted, artificial insemination is unlikely to be successful. These women often require in vitro fertilization in order to conceive. Although the studies of in vitro fertilization for women with severe endometriosis do not all show similar results, pregnancy success rates are usually good if the woman is relatively young and if she produces enough eggs during the ovarian stimulation.