EFFECT OF POST-COITAL CONTRACEPTIVE METHODS ON THE ENDOMETRIUM AND THE MENSTRUAL-CYCLE

Study objective. To evaluate the effect of treatment with ethinylester adiol-levonorgestrel or danazol on ovarian function, gonadotrophin rel ease and endometrial development during the time when a pregnancy may occur following unprotected intercourse. Methods. Women with regular m enstrual cycles were followed during one control one treatment and one follow-up month. The women obtained either a combination of 0.5 mg le vonorgestrel and 0.1 mg ethinylestradiol (Yuzpe regimen; n=16) or 600 mg danazol orally and repeated after 12 hours (n=16), The treatment wa s administered on either cycle day (ed) 12 or day LH+2. An endometrial biopsy was obtained once on ed LH+6 to +8 in the subjects treated on ed LH+2 both in control and treatment cycles, and morphometric analysi s was performed. The concentrations of LH, pregnandiol (P2G), and estr one (E1C) glucuronide were followed daily in morning urine during cont rol and treatment cycles. Results. Following treatment with the Yuzpe regimen on ed 12 the LH surge was either undetectable (three subjects) , postponed to ed 16 to 22 (three subjects) or ed 38 to 39 (two subjec ts) with lower P2G and LH levels than in the control cycle. Following preovulatory treatment with danazol, no LH peak could be detected in f our subjects and in the remaining four subjects the LH peak varied bet ween ed 13 and ed 24. The mean area under the curve for LH was signifi cantly lower, the levels of E1G were slightly higher and the P2G level s were unaffected in comparison with the control cycle. Neither of the two treatments administered on ed LH+2 affected the hormonal pattern and only a discreet effect on the development of the endometrium was s een after the EE/LNG treatment. Conclusion. The findings indicate that the contraceptive effect of postcoital treatment with EE/LNG and dana zol is mainly due to an inhibition or delay of ovulation and insuffici ent corpus luteum function. The direct effect on the endometrium is li mited, if any.