Withholding gonadotropins ("coasting") to minimize the risk of ovarian hyperstimulation during superovulation and in vitro fertilization-embryo transfer cycles

Objective: To evaluate superovulation (SOV) and IVF-ET cycles in which E-2 levels were allowed to decrease to restrain rapid follicular growth and min imize the risk of ovarian hyperstimulation syndrome. Design: Retrospective series. Setting: Tertiary care infertility practice. Patient(s): Women who underwent SOV (n = 51) and IVF-ET (n = 93) treatment and who were at risk for OHSS. Intervention(s): In SOV cycles, hMG was withheld (coasting) for >3 days bef ore hCG administration. until follicular maturity was attained (greater tha n or equal to 3 follicles of greater than or equal to 18 mm) and E-2 levels decreased, In IVF-ET cycles, either follicular maturity was attained befor e coasting (n = 63), allowing hCG administration after E-2 levels decreased by >25%, or coasting occurred before follicular maturation (n = 30), neces sitating the administration of additional hMG after coasting. Main Outcome Measure(s): Estradiol concentrations, follicle size, and pregn ancy rates. Result(s): Estradiol concentrations usually rose for greater than or equal to 1 day after coasting began, then Fell by greater than or equal to 25% wh ile follicle numbers and mean diameters increased. No spontaneous LH surges occurred, although four SOV cycles were canceled because of excessive foll icular development. Of the women who received hCG, 11 of 47 (23% per cycle) conceived during SOV and 35 of 93 (37.6% per cycle) conceived during IVF-E T. Seven ovarian hyperstimulation syndrome developed in 1 woman who underwe nt IVF-ET. Conclusion(s): Coasting can safely rescue overstimulated SOV and IVF-ET cyc les characterized by an excessive rise in E-2 levels and/or numerous incomp letely mature follicles. (Fertil Steril(R) 1999;71:294-301. (C) 1999 by Ame rican Society for Reproductive Medicine.).