Effect of progestogen therapy on follicular development, related hormone concentrations and fertilization in vitro in unstimulated cycles and unexplained and endometriosis-associated infertility

Evidence of pituitary-ovarian dysfunction in unexplained and endometriosis-associated infertility has been reported previously. Hormone-suppressive therapy is often used in an attempt to improve fertility, although benefits have not been proven. Our study examines the effect of progestogen (medroxyprogesterone acetate) treatment on women with endometriosis-associated and unexplained infertility, compared with women with tubal damage as functional controls. Pre-ovulatory follicular size and serum and follicular fluid hormone concentrations were measured, and oocyte collection and in-vitro fertilization were attempted, in natural cycles totally unperturbed by exogenous gonadotrophins, for two cycles before and two cycles following treatment with medroxyprogesterone acetate for 2 months. In the endometriosis and unexplained infertility groups, compared with the tubal group, the treatment led to significant reductions in the integrated luteinizing hormone (LH) values (483 versus 664, 559 versus 762 and 864 versus 820 notional IU/l respectively). There were no changes in serum oestradiol or follicular fluid oestradiol, progesterone, follicle stimulating hormone or LH concentrations after treatment. The results suggest that progestogen therapy has no beneficial effect on the pituitary-ovarian dysfunction which contributes to endometriosis-associated and unexplained infertility.