中文摘要：

促性腺激素释放激素激动剂（GnRH-a）短效长方案作为经典的＂金标准＂方案,扳机（trigger）时机范围多在主导卵泡在17至22mm,可获得稳定的妊娠结局。促性腺激素释放激素拮抗剂（GnRH-ant）方案作为一种新兴方案,广泛应用于临床。由于GnRH-ant方案和GnRH-a长方案作用机制及用药方案差异较大,扳机时机的选择非常关键。目前数据支持拮抗剂方案扳机时机与激动剂方案基本相同。推迟扳机可增加获卵数,MⅡ卵数和优胚率,但可能致孕酮升高,内膜提早发生分泌期改变,降低子宫内膜容受性。扳机时机的抉择需兼顾目标卵泡群的个数、大小,及内膜容受性等方面进行综合考虑。

英文摘要：

As a classic＂gold standard＂protocol,stable pregnancy outcome can be obtained by using the GnRH agonist long protocol.The timing of HCG in GnRH agonist cycles is usually on the day when one or more 17-22 mm follicles are present.As a newly emerging protocol,GnRH antagonist protocol is generally used in clinic.There is a big difference in the mechanism and medications between the GnRH agonist and antagonist protocol,so proper selection of trigger timing is very important.Existing data showed the trigger timing in GnRH antagonist protocol was similar as GnRH agonist protocol.Delaying administration of HCG can increase the numbers of oocytes retrieved,M Ⅱ oocytes and high quality embryos.However,it may also lead to progesterone elevation,higher incidence of endometrial development advancement,and lower endometrial receptivity.So the trigger timing should be based on the number and size of target follicles and endometrial receptivity.