A comparative randomized trial on the impact of two low-dose oral contraceptives on ovarian activity, cervical permeability, and endometrial receptivity.

ABSTRACT

PIP: The impact of two low-dose monophasic oral contraceptives (OCs) on suppression of ovarian activity, cervical permeability, and endometrial receptivity was investigated in a randomized double-blind study involving 118 healthy women 18-35 years of age recruited from 10 study centers in Germany. 59 women received Eve (20 mcg of ethinyl estradiol and 500 mcg of norethisterone) and 59 were given Lovelle (20 mcg of ethinyl estradiol and 150 mcg of desogestrel) for a total of 3 cycles. No ovarian activity, as assessed by sonographic determinations of follicle-like structures and serum endocrine profiles, was detected in 90.8% of cycles of Eve users and 97.2% of cycles in the Lovelle group. Follicular activity or cyst formation was found in 18 of 173 cycles of Eve users and 5 of 175 cycles of Lovelle users. Gonadotropin levels were suppressed (luteinizing hormone under 6 IU/L and follicle-stimulating hormone less than 8 IU/L) in 76.6% of treatment cycles in the Eve group and 84.8% of cycles in the Lovelle group. Serum estradiol concentrations exceeding 0.1 nmol/L, indicative of follicular activity, were recorded in 19.3% of cycles of Eve users and 12.2% of cycles in the Lovelle group. Although serum progesterone levels were over 5 nmol/L in 4.1% of cycles in the Eve group and 2.9% of those in the Lovelle group, consolidation of sonographic and endocrinologic data failed to document ovulation in any treatment cycles. The quantity and quality of cervical mucus was minimal in most women in both groups. Finally, the endometrial layer was determined to be low by ultrasonography during most pill cycles, confirming the OCs' equally strong suppressive effects on endometrial receptivity.