[Clinical outcome of patients with follicular development retardation by prolonged duration of gonadotropin administration for in vitro fertilization].

To investigate prolonged use of gonadotropin (Gn) stimulation for the patients with follicular development retardation during controlled hyperstimulation (COH) for in vitro fertilization (IVF) cycles.The inclusion criteria to categorize the good responder were that duration of Gn stimulation was < or = 15 days, total Gn dose used was < or = 3300 IU and total oocytes retrieved were > or = 4. The inclusion criteria for prolonged duration of Gn stimulation were that duration of stimulation was > or = 16 days. There were 69 oocyte retrieval cycles and 66 transfer cycles in prolonged stimulation group (group 1) and 483 oocyte retrieval cycles and 464 transfer cycles in good ovarian response group (group 2). The clinical characteristics and outcomes of two groups were analyzed.Clinical 5 pregnancy rate, implantation rate and delivery rate were 45.5% (30/66) versus 51.7% (240/464), 30.5% (385/1262) versus 28.0% (46/164) and 37.9% (25/66) versus 39.4% (183/464), respectively, in groups 1 and 2. Duration of Gn stimulation and dose were (20.8 +/- 4.2) and (10.3 +/- 1.8) days, (3090 +/- 1140) and (2302 +/- 862) IU in groups 1 and 2, respectively. There was no statistical difference in patient's age, basal follicular stimulating hormone (FSH), clinical pregnancy rate, implantation rate, early miscarriage rate, ovarian hyperstimulation syndrome (OHSS) rate, delivery rate between two groups (P > 0.05). There were more polycystic ovary (PCO) and (or) polycystic ovarian syndrome (PCOS) patients, more basal antral follicles, longer duration of Gn stimulation (range 16 - 33 days), higher Gn dose, lower serum peak estradiol (E(2)) level, fewer oocytes, fewer embryos transferred, in group 1 compared with group 2 (P < 0.01).These results demonstrate that prolonged Gn stimulation more than 16 days is a valuable alternative before cancellation of the IVF cycles for follicular development retardation during COH. Good clinical outcome can be achieved including pregnancy rate, implantation rate and delivery rate.