Abstract: AIM: To investigate the suboptimal dose of long-acting GnRH-a used for in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI).METHODS: Retrospective evaluation of long protocols for those patients undergoing IVF/ICSI from 2009 to 2010. Due to the dose of GnRH-a used in luteal metaphase, they were divided into three groups: <0.6 mg(Group A), ≥0.6 mg<0.8 mg(Group B),≥0.8 mg(Group C), in which randomly extract 100 cycles in each group. The clinical outcomes were observed.RESULTS: The transfer cycles of Group A, B, C were 92, 80, 85, respectively. In three groups, there were no significant differences in the rates of maturation, fertilization, high quality embryo, abortion and ectopic pregnancy(P>0.05). The plantation rate and clinical pregnancy rate per transfer were also higher in group A than thore group B and C(37.91% vs25.14% vs 23.16%, 63.04% vs 37.5% vs 41.18%, respectively, P<0.01). In group C, the total Gn amount was significantly larger (P<0.01), and the level of LH on Gn day and hCG day were both lower(P<0.05), compared with the other two groups.CONCLUSION: Long-actiong GnRH-a in very low dose could get perfect clinical outcome.

Key words: In vitro, Fertilization-embryo transfer, Gonadotropin-release hormone agonist, Long-acting