'Prolonged coasting': an effective method for preventing severe ovarian hyperstimulation syndrome in patients undergoing in-vitro fertilization.

Over a 4 year period ending 1 January 1995, 51 women scheduled for in-vitro fertilization (IVF) and embryo transfer were inadvertently severely overstimulated with menotrophins, as evidenced by the development of > 29 ovarian follicles in association with peak plasma oestradiol concentrations of > 6000 pg/ml. Accordingly, these women were at great risk of developing life-endangering complications associated with severe ovarian hyperstimulation syndrome (OHSS). Treatment involved withholding the administration of both menotrophins and human chorionic gonadotrophin for a number of days, while continuing gonadotrophin-releasing hormone agonist until the plasma oestradiol concentration fell to < 3000 pg/ml ('prolonged coasting'). The mean number of oocytes retrieved was 21.0, while the mean number of embryos transferred per procedure was 5.4. There were 21 clinical pregnancies (i.e. pregnancy rate of 41% per oocyte retrieval), 19 of which resulted in live births (i.e. a live birth rate of 37% per oocyte retrieval). Two pregnancies miscarried and there were four multiple gestations (three sets of twins and one set of triplets). None of the women developed severe OHSS. Prolonged coasting is an effective method of preventing the occurrence of severe OHSS without necessitating the cancellation of the IVF cycle or compromising success rates.