Endometriosis in pregnant and non-pregnant women at tubal sterilization.

The prevalence of endometriosis was investigated in 208 women at the time of laparoscopic tubal sterilization. In 101 women who were in the first trimester of pregnancy, 16% endometriosis was found. In 107 non-pregnant women, 22% endometriosis was detected. Endometriosis in the pregnant women showed more superficial, non-pigmented, gland-like lesions than in the non-pregnant group. In 23% of the endometriotic lesions from pregnant women, no decidualization was found. No special risk factors for developing endometriosis were found.