Individual versus standard dose of rFSH in a mild stimulation protocol for intrauterine insemination: a randomized study

BACKGROUND: Controlled ovarian stimulation (COS) and intrauterine insemination (IUI) are often used as the first-line treatment for subfertile couples. To minimize the variability in ovarian response in patients' first treatment cycle, we recently developed a recombinant follicle-stimulating hormone (rFSH) dosage nomogram. The nomogram has now been tested. METHODS: Multicentre randomized controlled trial (RCT) including 228 ovulatory patients scheduled for COS and IUI. Patients were randomized to 'individual' (50-100 IU rFSH/day, n = 113) or 'standard' (75 IU rFSH/day, n = 115) dose. 'Individual' dose was prescribed according to the nomogram, which was based on patients' body weight and antral follicle count. The primary end-point was the proportion of patients with two to three follicles > or = 14 mm (maximum two follicles > or = 18 mm) on the day of hCG (leading follicle = 18 mm). Primary analysis was made by intention-to-treat. RESULTS: In the 'individual' group, 79/113 (70%) of the patients developed two to three follicles versus 64/115 (56%) in the 'standard' group [absolute difference = 14.3 percentage points; 95% confidence interval (CI) 2-26, P = 0.03; absolute difference = 14.4; 95% CI 2-27, P = 0.02, when adjusting for centre]. Among patients with two to three follicles, the proportion of patients with two follicles was 46/79 (58%) in the 'individual' group versus 34/64 (53%) in the 'standard' group, P = 0.54. Ongoing pregnancy rate was 23/113 (20%) in the 'individual' group and 21/115 (18%) in the 'standard' group and the rate of multiple gestations was 1/113 (1%) versus 5/115 (4%), P = 0.21. CONCLUSIONS: This RCT is the first to clinically test a dosage nomogram in ovulatory IUI patients' first rFSH treatment cycle. Dosing according to the nomogram was superior to standard dosing. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT00374634.