Individualized dosing of rec-FSH for ovarian stimulation in women with PCOS reduces asynchronous follicle growth

We aimed to evaluate if ovarian stimulation with individualized dosing of recombinant follicle-stimulating hormone (rec-FSH) with follitropin delta compared with standard gonadotropin dosing reduce occurrence of follicular asynchrony in women with polycystic ovary syndrome (PCOS) undergoing in vitro fertilization (IVF).

Matched case–control study analyzed occurrence of follicular growth asynchrony during ovarian stimulation and IVF outcomes in women with PCOS. Follicular growth was considered to be asynchronous when one or two leading follicles were at least 4 mm larger in diameter than the rest of the cohort on day 5 and 9 of stimulation. Analysis encompassed 44 women stimulated with individualized rec-FSH dosing, and 88 women treated with standard dosing. The patients were matched in terms of age, Anti-Müllerian hormone levels and body weight.

Early and late follicular asynchrony were present less frequently in individualized dosing compared to standard dosing group (4.5% vs 17%, p = 0.04 and 2.3% vs 37.5%, p < 0.001, on stimulation day 5 and 9, respectively). Multivariate logistic regression on follicular asynchrony revealed that individualized dosing significantly decreases the occurrence and chances for late follicular asynchrony (Odds Ratio 0.28, p < 0.001). Shorter duration of stimulation (9.6 vs 10.4 days, p = 0.001), lower total gonadotropin dose (1118 vs 1940 IU, p < 0.001), higher number of metaphase II oocytes (7.1 + 4.3 vs 5.4 ± 3.0, p = 0.001), good quality embryos (3.8 vs 2.0, p < 0.001), and implantation rates (31.0 vs 23.4, p = 0.04) were observed in the individualized dosing group.

Individualized rec-FSH dosing reduces asynchronous follicular growth and improves ovarian stimulation efficiency in women with PCOS undergoing IVF.