The changes in the hypothalamic-pituitary-ovarian axis during the placebo week in oral contraceptive pill users were assessed. Fifteen women using the combined oral contraceptive pill were studied for eight hours at the start and at the end of the placebo week and gonadotropin secretion and estradiol concentrations were compared with those in control women in the follicular phase of an unmedicated menstrual cycle. Both gonadotropin and estradiol concentrations were suppressed at the start of the placebo week. By day 7 of placebo, gonadotropin concentrations and pulse patterns were indistinguishable from those of the control subjects although estradiol concentrations were still significantly lower.
PIP: The changes in the hypothalamic-pituitary-ovarian axis during the placebo week in oral contraceptive (OC) users were assessed. 15 women who used a combined OC were studied for 8 hours at the start and at the end of the placebo week; gonadotropin secretion and estradiol concentrations were compared with those in control women during the follicular phase of an unmedicated menstrual cycle. Both hormone concentrations were suppressed at the start of the placebo week. By day 7 of placebo, gonadotropin concentrations and pulse patterns were indistinguishable from those of the controls although estradiol concentrations were still significantly lower.