Prediction of the Individual Follicle-stimulating Hormone Threshold for Gonadotropin Induction of Ovulation in Normogonadotropic Anovulatory Infertility: an Approach to Increase Safety and Efficiency

Objective: To predict the FSH response (threshold) dose in normogonadotropic, anovulatory infertile women undergoing gonadotropin induction of ovulation.

Design: Prospective longitudinal clinical study.

Setting: Specialist academic fertility unit.

Patient(s): Normogonadotropic, oligoamenorrheic, infertile women who were resistant to clomiphene citrate or in whom clomiphene citrate therapy had failed.

Intervention(s): Daily exogenous FSH administration in a low-dose, step-up regimen.

Main Outcome Measure(s): The FSH dose on the day of ovarian response (follicle growth > 10 mm in diameter).

Result(s): Multivariate analysis was used to devise the following equation to predict the individual FSH response dose (75 to >187 IU/d) before initiation of therapy: [4 body mass index (in kg/m(2))] + [32 clomiphene citrate resistance (yes = 1 or no = 0)] + [7 initial free insulin-like growth factor-I (in ng/mL)] + [6 initial serum FSH level (in IU/L)] - 51. The SE of the predicted dose is 35 IU.

Conclusion(s): The individual FSH response dose for gonadotropin induction of ovulation in anovulatory infertile women can be predicted on the basis of initial screening characteristics. The prediction model developed in this study may increase the safety and efficiency of low-dose gonadotropin protocols (step-up and step-down) by correctly determining the appropriate starting dose for a given patient.