Comparison of Assisted Reproductive Technology (ART) Outcomes in Two Controlled Ovarian Stimulation Protocols Using Follitropin Delta, a Recombinant Follicle-Stimulating Hormone (rFSH) Injection

Aim: This study aimed to compare the outcomes of assisted reproductive technology (ART) between progestin-primed ovarian stimulation (PPOS) and antagonist protocols, using follitropin delta as the sole ovarian stimulation agent. While many comparative studies on PPOS and antagonist protocols exist, most utilize follitropin alpha or beta as stimulatory agents. Notably, no studies have reported on the use of follitropin delta in this context. Methodology: A retrospective analysis was conducted on ART cases initiated in 2022, including 529 PPOS cycles and 298 antagonist cycles. Subgroup analyses were performed based on anti-Müllerian hormone (AMH) levels, dividing patients into four groups: <1.2 ng/mL, 1.2≤ AMH <2.03 ng/mL, 2.03≤ AMH <5.0 ng/mL, and ≥5.0 ng/mL. Assessed outcomes included the number of retrieved oocytes, fertilization rates, cleavage rates, blastocyst formation rates (BL rates), and good-quality blastocyst formation rates (GBL rates), as well as the number of retrieved oocytes, fertilized embryos, cleavage-stage embryos, BL, and GBL. All cases were planned for complete blastocyst vitrification, including those in the antagonist group. Results: The mean patient age was 35.1 years in the PPOS group and 36.2 years in the antagonist group. Other baseline characteristics included the causes and duration of infertility, proportion of primary infertility, baseline hormone levels, BMI, duration and dosage of follitropin delta administration, and duration of medroxyprogesterone acetate (MPA) use. There were no significant differences in the background characteristics between the two groups. In AMH levels of 2.03 ng/mL and above, the two groups with AMH-based subgroups showed that the PPOS protocol demonstrated a significantly higher number of retrieved oocytes, BL, and GBL compared to the antagonist protocol. Conclusion: While previous studies have indicated that no significant differences in outcomes between these protocols, the present study observed that the follitropin delta enhanced the formation of blastocysts and good-quality blastocysts. Further research is needed to determine whether these findings are specific to follitropin delta or extend to other recombinant follicle-stimulating hormone (rFSH) preparations.