150 IU vs. 225 IU FSH in Normal Responders: The OPTIMAL-DOSE Trial

Overview

This is a single-center, randomized, open-label, non-inferiority trial comparing two fixed daily doses of follicle-stimulating hormone (FSH): 150 IU versus 225 IU in women with predicted normal ovarian response undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) with a gonadotropin releasing hormone (GnRH) antagonist protocol. The primary objective is to determine whether the 150 IU dose is noninferior to the 225 IU dose regarding the cumulative live birth rate per initiated cycle. Secondary objectives include comparing oocyte yield, incidence of OHSS, treatment costs, and patient-reported outcomes.

Background: Controlled ovarian stimulation (COS) with exogenous FSH is a cornerstone of IVF treatment. The optimal starting dose of FSH for women with normal ovarian reserve remains controversial, with doses ranging from 150 IU to 300 IU used in clinical practice. Both 150 IU and 225 IU are widely used, but no randomized controlled trial has directly compared these two specific doses in predicted normal responders. Objective: To determine if a fixed daily dose of 150 IU FSH is non-inferior to 225 IU FSH with respect to cumulative live birth rate per initiated cycle. Methods: A total of 440 women (220 per group) will be randomized 1:1 to receive either 150 IU or 225 IU of FSH daily, starting on day 2-3 of the menstrual cycle. All participants will follow a standard GnRH antagonist protocol. The primary outcome is cumulative live birth rate, defined as the delivery of at least one live-born infant at ≥24 weeks of gestation from the first fresh or any subsequent frozen embryo transfer from a single stimulation cycle. The non-inferiority margin is set at -10% (absolute difference). Significance: If 150 IU is proven non-inferior, this would support the use of a lower dose, potentially reducing treatment costs and the risk of ovarian hyperstimulation syndrome (OHSS) without compromising efficacy.