Effect of endometriosis on fertility

The endometrium is the tissue that lines the inside of the uterine cavity. Endometriosis is an abnormal condition where some endometrial tissue has spread elsewhere outside the uterus – such as to the ovaries (chocolate cysts), pelvic cavity, intestines, ligaments, bladder, rectum etc.

Endometriosis may be symptomatic or asymptomatic. It causes pain in some women and can also cause infertility. About 5-10% of all women have endometriosis. It is important to remember that not all women with endometriosis are infertile. Many women conceive without difficulty and eventually have a successful pregnancy, sometimes even before diagnosis. However, 1/3 rd of these women have trouble conceiving.

1. The inflammation and irritation caused by endometriosis can affect fertility due to alterations in the immune response.

2. Toxins in the fluid in the pelvic cavity disrupt the normal reproductive biochemistry, altering the hormonal balance that aids infertility.

3. Swelling and scarring of the fimbria ( terminal part of the tube) due to inflammation affects egg pick up and transport into the fallopian tube

4. Endometriosis can also block the fallopian tubes due to tubal and peri tubal adhesions

5. Problems with the quality of eggs as they are exposed to a hostile environment caused by endometriosis.

6. Problems with the embryo travelling down the tube and implanting in the wall of the uterus due to damage from endometriosis

7. In more advanced cases, the endometriosis starts to cause marked adhesions, and the pelvic organs become stuck to each other (frozen pelvis), resulting in the egg getting trapped and hence infertility.

Most patients are suggested IUI or IVF after trying naturally for some time depending upon the severity of endometriosis. However, the success rates of these treatments may vary although not proven to be significantly lower when compared to the normal population. Causes of probable low success rates in IUI or IVF may be due to:

1. Altered tubal motility and sperm transport due to adhesions

2. Hostile environment for gametes (sperms and eggs) in vivo, inhibited sperm motility.

3. Fewer eggs retrieved after ovarian stimulation.

4. Altered uterine receptivity.

5. Altered immune response.

6. Thick zona pellucida ( membrane covering egg)

The good news is that there are many women every day with endometriosis who conceive and ultimately deliver a healthy baby. The key is to start discussing your conception options, sometimes even before you think about getting pregnant. When you’re trying to get pregnant, see your doctor if you haven’t conceived after six months or earlier in certain circumstances like advanced age, previous endometriosis surgeries etc. Combination of good stimulation techniques, efficient surgery if indicated, proper selection of patients for a particular treatment modality are crucial for good outcomes.