A study of plasma progesterone, oestradiol-17beta, prolactin and LH levels, and of the luteal phase appearance of the ovaries in patients with endometriosis and infertility.

Thirty-four infertile patients with regular cycles and endometriosis were studied and compared to a control group of 28 women. The endometriosis was classified as mild (n = 16), moderate (n = 9) and severe (n = 9) according to Acosta et al (1973). The interval between the LH peak and the onset of subsequent menstruation was shorter (P = 0.024) in patients with endometriosis than in the control group. In mild endometriosis, oestradiol-17beta levels fell on the day after the LH peak, but this was not the case in moderate and severe endometriosis. In mild, moderate and severe endometriosis the plasma progesterone concentration did not rise on the first day following the LH peak, and at laparoscopy significantly (P less than 0.005) less ovulation stigmata were present. We conclude that endometriosis is associated with luteinization in situ and that this may explain the associated infertility.