Received April 07, 2026
Accepted April 13, 2026

Objective: To characterize prescription patterns, dosing, ovarian response, and reproductive outcomes associated with follitropin delta in routine Brazilian assisted reproduction practice Methods: Multicentric retrospective cohort trial in five private IVF centers in Brazil. A total of 2,284 women (18-47years) treated with follitropin delta between April-2018 and December-2023 were enrolled. Controlled ovarian stimulation was administered as mono or combined therapy; starting dose was calculated by AMH/weight algorithm or physician discretion. Outcomes analyzed: stimulation protocol distribution, follitropin delta doses, oocyte yield, fertilization and blastocyst rates, ongoing pregnancy rate, moderate/severe OHSS. Results: Protocol distribution was algorithm guided monotherapy 1.9%, empirical monotherapy 14.8%, delta + menotropin 75.3%, delta + rFSH/LH 5.0%, other combinations 3.0%. Mean±SD oocytes retrieved were 12.9±9.5. Pituitary suppression used mainly GnRH antagonist (50.7%) and PPOS (45.8%). Final trigger used GnRH agonist (47.7%), hCG (11.0%), and dual trigger (41.3%). Among patients, 1,448 (63.4%) had autologous IVF/ICSI cycles, 705 (30.9%) oocyte cryopreservation cycles, 131 (5.7%) oocyte donation cycles. Overall, 94.7% of patients underwent oocyte pick-up (mean of 12.9 oocytes retrieved). In 1448 IVF patients, 971 had up to four embryo transfers. Ongoing pregnancy rates were 50.3 % (360/715), 42.4 % (81/191), 24.5 % (12/49), and 56.1 % (9/16) across the first to fourth transfers, respectively; severe OHSS occurred in 0.2% of IVF patients. Conclusions: Follitropin delta was used predominantly in mixed protocols with menotropin, with robust oocyte numbers, high ongoing pregnancy rates, and low incidence of severe OHSS. This reinforces effectiveness and safety of individualized dosing and clinical value of combining follitropin delta with other gonadotropins for ovarian stimulation.