The ovulation trigger–OPU time interval of different ovarian protocols in ART: a retrospective study

PURPOSE: To explore the trends of oocyte and pregnancy outcomes over the ovulation trigger–OPU (oocyte pickup) time interval in four mainly used COH protocols. METHODS: This retrospective study was conducted between January 2013 and July 2018. The IVF/ICSI cycles of the patients with normal ovarian reserve were included. The number of total patients was 4673, which consisted of long agonist protocol (n = 819), short agonist protocol (n = 1703), mild stimulation protocol (n = 1627), and GnRH antagonist protocol (n = 524). The primary outcome was mature oocyte rate. RESULTS: The ovulation trigger–OPU time interval and COH protocol were related to cycles with > 80% MII oocytes. Four protocols showed apparently different trends of retrieved oocyte rate and mature oocyte rate over the ovulation trigger–OPU time interval, and the long agonist protocol had the most delayed time interval than other three COH protocols in retrieving more than 60% oocytes (35.4–39.6 h vs. 34.6–38.6 h vs. 32.5–37.5 h vs. 33.8–37.7 h) and getting more than 80% mature oocytes (35.0–39.7 h vs. 36.0–37.7 h vs. 34.1–35.5 h vs. 34.5–36.3 h). And the adjusted odds ratio (OR) of the cumulative live birth rate (CLBR) (OR 1.360, 95% Confidence Interval (CI) 1.156–1.549, P < 0.05) significantly increased with the trigger–OPU time interval in the long agonist protocol. CONCLUSIONS: For getting more and mature oocytes, the ovulation trigger–OPU time intervals should be gradually prolonged from the mild stimulation protocol, the GnRH antagonist protocol, and the short protocol to the long agonist protocol. And the prolonged ovulation trigger–OPU time interval in the long agonist protocol brings higher live birth rate (LBR) and CLBR. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s00404-020-05568-5) contains supplementary material, which is available to authorized users.