Endometriosis is a major cause of female infertility
Endometriosis is a condition in which endometrial tissue, the tissue that lines the inside of the uterus, grows outside the uterus and attaches to other organs in the abdominal cavity such as the ovaries and fallopian tubes. Endometriosis is a progressive disease that tends to get worse over time and can reoccur after treatment. Symptoms include painful menstrual periods, abnormal menstrual bleeding and pain during or after sexual intercourse.
The endometrial tissue outside your uterus responds to your menstrual cycle hormones the same way the tissue inside your uterus responds – it swells and thickens, then sheds to mark the beginning of the next cycle. The blood that is shed from the endometrial tissue in your abdominal cavity has no place to go, resulting in pools of blood causing an inflammation that forms scar tissue. The scar tissue can block the fallopian tubes or interfere with ovulation. Another result of endometriosis is the formation of ovarian cysts called endometriomas that may also interfere with ovulation.
In patients with endometriosis, the chance of conception decreases by 20 – 30%. However, the long term pregnancy rates are the same in patients with minimal endometriosis and normal anatomy (i.e., open tubes). Studies provide contradicting information, but the bulk of research at this time indicates that pregnancy rates are not improved by treating minimal endometriosis. In cases where there is obvious distortion of the normal anatomy (i.e. blocking the fallopian tubes), endometriosis is a known cause of infertility. In fact 30-40% of patients with endometriosis are infertile. This is two to three times the rate of infertility in the general population.
We know that during in vitro fertilization, endometriosis patients have normal hormonal profiles. There is a tendency towards obtaining fewer eggs and it appears that eggs derived from ovaries with endometriomas may have a lower fertilization rate and implantation rate.
The immune system is affected by endometriosis and this may also affect fertility. Patients with endometriosis may show decreased nature killer cell function. In addition, complement, an immune component that breaks apart abnormal cells, is higher in patients with endometriosis.