Preovulatory luteinization during induction of follicular maturation with menotrophin and menotrophin--clomiphene combination.

Late follicular phase levels of 17 beta-oestradiol (E2) and progesterone (P) in serum were studied during the induction of follicular maturation with human menopausal gonadotrophin (HMG) (n = 23) and HMG-clomiphene citrate (CC) (n = 18). For each patient one hormonal profile was studied between 6 days to 2 h before administration of human chorionic gonadotrophin (HCG). Ultrasonographic follicular measurement at the time of evaluation demonstrated preovoulatory ovarian follicles of various number and size in all patients studied. Sixteen endometrial biopsies were performed at the time of evaluation (eight for each subgroup), before HCG administration. Mean late follicular phase levels of E2 did not differ significantly between the two groups (436 +/- 348 and 475 +/- 267 pg/ml for the HMG and HMG-CC groups respectively). The mean progesterone levels in the HMG-CC group (1.233 +/- 0.67 ng/ml) was significantly higher than that for the HMG group of (0.86 +/- 0.55 ng/ml, P less than or equal to 0.04). The mean time interval between ovulation and HCG administration for the two groups was 2.5 and 2.4 days for the HMG and HMG-CC groups, respectively. In all eight biopsies taken from the HMG group, various stages of endometrial proliferation were demonstrated. Premature glandular secretory transformation and oedematous stroma were observed in three out of eight biopsy specimens obtained from the HMG-CC group. Taken together, these results demonstrate that subtle or full premature luteinization in the late follicular phase occurs more frequently with the use of HMG-CC for induction of follicular maturation.