Research question: Gonadotrophin releasing hormone (GnRH) agonist trigger after GnRH antagonist-based ovarian stimulation protocol for IVF is gaining popularity, because it prevents ovarian hyperstimulation syndrome and allows for near physiological LH and FSH surges. A small dose of HCG (1500 IU) on the day of oocyte retrieval, followed by daily progesterone administration, is currently the preferred way to secure adequate luteal support after GnRH agonist trigger. In the present study, the possibility that a bolus of 1500 IU HCG, given 2 days after oocyte retrieval, may be sufficient to sustain adequate luteal support without additional progesterone treatment was questioned.

Design: A non-interventional retrospective cohort study between conducted between April 2017 and August 2018. A total of 154 consecutive patients treated with GnRH agonist trigger followed by day-2 HCG (1500 IU) support only (study group) were included. Data were compared with 155 consecutive patients who were treated with HCG (6500 IU) trigger followed by conventional progesterone luteal support (control group).

Results: Pregnancy, miscarriage and live birth rates were comparable between the study and control groups. In patients who became pregnant, mean oestradiol level 14 days after oocyte retrieval was 4719 pmol/l and 2672 pmol/l in the study and control group, respectively (P < 0.001), reflecting robust luteal activity in the study group.

Conclusions: A bolus of 1500 IU HCG, administered 2 days after retrieval, can provide excellent luteal support, without the need for further progesterone supplementation.

研究问题：基于 GnRH 拮抗剂的 IVF 卵巢刺激方案后促性腺激素释放激素 (GnRH) 激动剂触发越来越受欢迎，因为它可以预防卵巢过度刺激综合征并允许接近生理的 LH 和 FSH 激增。在取卵当天服用小剂量 HCG (1500 IU)，然后每天服用黄体酮，是目前在 GnRH 激动剂触发后确保足够黄体支持的首选方法。在本研究中，在取卵后 2 天给予 1500 IU HCG 的推注可能足以维持足够的黄体支持而无需额外的黄体酮治疗的可能性受到质疑。

设计：一项在 2017 年 4 月至 2018 年 8 月期间进行的非干预性回顾性队列研究。共纳入 154 名连续接受 GnRH 激动剂触发治疗的患者，随后仅接受第 2 天 HCG (1500 IU) 支持（研究组）。数据与 155 名连续接受 HCG (6500 IU) 触发治疗和常规黄体酮支持治疗的患者（对照组）进行了比较。

结果：研究组和对照组之间的妊娠率、流产率和活产率具有可比性。在怀孕的患者中，研究组和对照组取卵后 14 天的平均雌二醇水平分别为 4719 pmol/l 和 2672 pmol/l（P < 0.001），反映了研究组的黄体活性强。

结论：在取出后 2 天给予 1500 IU HCG 推注，可以提供极好的黄体支持，而无需进一步补充黄体酮。