RESUMEN
PIP: Urinary estrogen and serum gonadotropin were measured via fluorometric and radioimmunoassay techniques in 14 presumptively ovulatory women ingesting contraceptives of variable estrogen content. Blood and urine samples were collected on days 6-8, 12-17, and 22-24 of control and therapeutic cycles, and data were used to calculate mean hormone levels for respective cycle phases. Contraceptive formulations contained 1 mg norethindrone acetate and either 20 mcg or 50 mcg ethinyl estradiol. Consistently higher estrogen levels and higher luteinizing hormone levels were found in women ingesting norethindrone acetate 1 mg plus 20 mcg ethinyl estradiol. These differences were statistically significant and were consistently more pronounced during the early phase of therapeutic cycles. These findings may reflect possibly enhanced luteinizing-hormone-mediated ovarian steroidogenesis in the absence of apparent ovulation.^ieng