Comparable Euploidy and Aneuploidy Patterns Between Utrogestan-Based Progesterone-Primed Ovarian Stimulation and GnRH...

Objectives: This study compared controlled ovarian hyperstimulation (COH) outcomes and chromosomal euploidy results between the Utrogestan-based progesterone-primed ovarian stimulation (PPOS) and gonadotropin-releasing hormone antagonist (GnRH-Ant) protocols in preimplantation genetic testing for monogenic disorders (PGT-M) cycles, and assessed the efficacy and safety of the Utrogestan-based PPOS protocol. Methods: In this retrospective single-center cohort study, 176 PGT-M cycles managed with the Utrogestan-based PPOS protocol were compared with 176 GnRH-Ant cycles using 1:1 direct caliper matching without replacement. Embryos were classified as euploid, mosaic, aneuploid, or no-call according to next-generation sequencing results. The primary outcomes were euploidy rate and chromosomal aberration patterns; secondary outcomes included COH outcomes and pregnancy outcomes. Results: Baseline characteristics were comparable after matching. The total gonadotropin (Gn) dose was significantly lower in the Utrogestan-based PPOS group (2100 (1500-3000) vs. 2250 (1800-3000), p = 0.035). PGT analysis revealed comparable rates of euploidy, aneuploidy, mosaicism, and "No-call" between the Utrogestan-based PPOS (n = 586) and GnRH-Ant (n = 605) groups. The unadjusted difference in euploidy rate per MII oocyte between groups (18.98% vs. 16.36%, p = 0.045) was no longer statistically significant after multivariable adjustment (p = 0.194). In addition, patterns of aneuploidy and chromosomal involvement were similar between groups. The Utrogestan-based PPOS group showed numerically higher clinical pregnancy rate (70.67% vs. 63.22%) and live birth rate (62.67% vs. 51.72%), and a lower early abortion rate (5.66% vs. 12.73%), but none of these differences were statistically significant. Conclusions: Compared with the GnRH-Ant protocol, the Utrogestan-based PPOS protocol required a significantly lower total Gn dose while exhibiting comparable euploidy rate, analogous chromosomal abnormality spectrums, and pregnancy outcomes. The Utrogestan-based PPOS protocol may be a feasible alternative ovarian stimulation strategy in PGT-M cycles.