Effect of age on the response of the hypothalamo-pituitary-ovarian axis to a combined oral contraceptive

Objective: To examine the effect of age on the response to treatment with a combined oral contraceptive. Design: Prospective, controlled clinical study. Setting: Reproductive medicine unit in a tertiary care university medical center. Patient(s): Twenty-six healthy female volunteers aged 21-45 years. Intervention(s): After a control cycle, all the women were given a combined oral contraceptive containing 20 mu g Of ethinylestradiol with 75 mu g of gestodene for three cycles. The women were examined through the posttreatment cycle. Main Outcome Measure(s): Pituitary and ovarian activity was assessed with ultrasound and measurement of ovarian steroids. Result(s): Follicular activity was observed in all treatment cycles, although ovulation was inhibited. Ovarian suppression was maximal in cycle 1. Mean endogenous E-2 levels were lower during cycles 2 and 3 in the older group. Serum FSH levels were higher in the control cycle and on day 28 of the treatment cycles in the older group. Most women ovulated during the posttreatment cycle. Conclusion(s): Combined oral contraceptives did not inhibit all ovarian activity; maximal suppression was seen in cycle 1. Less follicular activity was observed in cycles 2 and 3 in the older group. Raised FSH levels with age reflect increasing ovarian resistance to follicular development. (Fertil Sterile(R) 1999,71.1079-84. (C) 1999 by American Society for Reproductive Medicine.).