In women aged 21‑37 undergoing IVF with genetic testing of embryos, using a short GnRH‑agonist stimulation plan led to more embryos with chromosome problems than the standard long GnRH‑agonist plan, especially in younger women with good ovarian reserve. The antagonist plan performed about the same as the long plan.

This study aimed to explore whether different controlled ovarian hyperstimulation (COH) protocols were associated with the incidence of aneuploid blastocysts in cycles undergoing preimplantation genetic testing for aneuploidy (PGT-A). A retrospective analysis was conducted on 5525 blastocysts from 1722 women (21-37 years old) who underwent PGT-A cycles utilizing next-generation sequencing (NGS). The cohorts included 240 cycles employing the gonadotropin-releasing hormone agonist (GnRH-a) short protocol, 698 cycles using the GnRH-a long protocol, and 784 cycles utilizing the GnRH antagonist (GnRH-ant) protocol. A significantly elevated rate of blastocyst aneuploidy was observed in the GnRH-a short protocol group relative to both the long protocol and antagonist protocol groups (44.05% vs. 36.00% vs. 37.90%). Multivariable regression analyses, with the GnRH-a long protocol serving as the reference category, indicated that the short protocol was independently correlated with higher aneuploidy rates (OR = 1.30, 95% CI 1.06-1.60, P = 0.012). This association was particularly evident among younger patients (< 35 years) possessing preserved ovarian reserve (AMH ≥ 1.2 ng/mL) (OR = 1.38, 95% CI 1.02-1.87, P = 0.036). Although non-significant, the short protocol also trended towards a higher aneuploidy rate compared to the antagonist protocol (OR = 1.12, 95% CI 0.89-1.41, P = 0.32). The findings suggest that, in the population studied (21-37 years), the GnRH-a short protocol is associated with a higher incidence of blastocyst aneuploidy compared to the long protocol, particularly in younger individuals (< 35 years) with normal ovarian reserve (AMH ≥ 1.2 ng/mL). These results highlight the need for tailored COH protocol selection based on patient characteristics in PGT-A cycles.