目的:探讨控制性促排卵(COS)hCG注射日雌二醇(E2)在hCG扳机时的作用。方法:接受长方案垂体降调节IVF/ICSI-ET助孕的不孕症患者1 811例,测量COS周期中E2水平,计算E2增幅[E2增幅=(hCG注射日E2值-hCG注射前日E2值)/hCG注射前日E2值]。按照E2的增幅分为5组:A1组E2增幅≤-10%,A2组E2增幅为-9%~10%,A3组E2增幅为11%~50%,A4组E2增幅为51%~100%,A5组E2增幅>100%;另按hCG注射日每卵泡E2水平分为5组:B1组E2≤200 pg/ml,B2组E2为201~300 pg/ml,B3组E2为301~400 pg/ml,B4组E2为401~500 pg/ml,B5组E2>500 pg/ml。比较各组间一般临床特征及IVF-ET的临床结局。结果:①A1组hCG注射日直径≥14 mm卵泡数、获卵数及2PN数较其他4组高,hCG注射日直径≥18 mm卵泡比例,较其他4组低,差异均有统计学意义(P<0.05),临床妊娠率偏低,但与其余4组间无统计学差异(P>0.05);②A5组hCG注射日P水平、hCG注射日直径≥14 mm卵泡数、获卵数、2PN数、临床妊娠率和胚胎着床率均较其他4组低,差异有统计学意义(P<0.05);③B2组临床妊娠率和胚胎着床率较其他4组高,差异有统计学意义(P<0.05)。结论:hCG注射日E2增幅介于-9%~100%、每成熟卵泡E2值介于201~300 pg/ml之间是hCG扳机的最佳时机。 Objective: To investigate the role of estradiol (E2) on hCG trigger during the control ovulation induction (COS) hCG injection. METHODS: A total of 1 811 infertile women receiving long-term pituitary down-regulation of IVF / ICSI-ET were enrolled. E2 levels in the COS cycle were measured and the E2 increase was calculated [E2 increase = E2 value on day hCG-E2 day before hCG injection ) / hCG E2 value before injection day]. According to the increase of E2, the patients were divided into 5 groups: the increase of E2 in group A1 was ≤-10%, the increase of E2 in group A2 was -9% -10%, the increase of E2 in group A3 was 11% -50%, and the increase of E2 in group A4 was 51% -100 %, The increase of E2 in group A5 was> 100%. The level of E2 in follicles was also divided into 5 groups on the day of hCG injection: E2≤200 pg / ml in group B1, 201-300 pg / ml in group B2 and 301 ~ 400 pg / ml, B4 group E2 401 to 500 pg / ml, B5 group E2> 500 pg / ml. The general clinical characteristics and clinical outcome of IVF-ET were compared between groups. Results: (1) The number of follicles with the diameter ≥ 14 mm on the day of injection on the day of hCG in group A1 was higher than that of the other 4 groups, and the proportion of follicles with the diameter of ≥ 18 mm on the day of hCG injection were lower than the other 4 groups (P <0.05). The clinical pregnancy rate was low, but there was no significant difference with the other 4 groups (P> 0.05) .②The level of P in hCG on day A5, the number of follicles on day of hCG ≥14 mm, the number of oocytes retrieved, the number of 2PN , The clinical pregnancy rate and embryo implantation rate were lower than the other 4 groups, the difference was statistically significant (P <0.05); ③ The clinical pregnancy rate and embryo implantation rate in group B2 were higher than the other 4 groups, the difference was statistically significant (P <0.05). CONCLUSIONS: The increase in E2 between days hCG injection is between -9% and 100%, and the E2 value of every mature follicle between 201 and 300 pg / ml is the optimal timing for hCG triggering.