THE UTILITY OF A MIDCYCLE FOLLICLE-STIMULATING-HORMONE BOOST IN ADDITION TO HUMAN CHORIONIC-GONADOTROPIN FOR TIMING OF FOLLICLE ASPIRATION IN UNSTIMULATED IN-VITRO FERTILIZATION CYCLES

Purpose: To analyze the effects and potential benefits of a single mid cycle dose of follicle-stimulating hormone (FSH) prior to human chorio nic gonadotropin (hCG) administration during unstimulated in vitro fer tilization (IVF) cycles. Methods: Twenty-five cycles from 20 patients receiving 150 IU of FSH 42-44 h and 10,000 IU of hCG 34-36 h prior to follicle aspiration were compared to 110 cycles triggered with hCG alo ne. Results: Serum E(2) levels were significantly lower on the day of hCG treatment in the FSH-treated group (266 vs. 297 pg/ml). On the day after hCG administration, serum E(2) was similar in both groups. Maxi mum follicular diameters the day of and the day after hCG treatment we re similar as were the number of oocytes aspirated and embryos transfe rred, and clinical pregnancy rates in bath groups. The number of cycle s dropped due to premature luteinizing-hormone (LH) surge was 8% in th e FSH group compared to 20% in the group treated with hCG alone. Concl usions: A midcycle FSH boost does net increase pregnancy success of un stimulated IVF cycles but does enhance the increase in serum E(2) leve ls after hCG, thereby potentially allowing earlier hCG administration while incurring decreased cycle cancellation rates due to premature LH surges.