FSH response-dose can be predicted in ovulation induction for normogonadotropic anovulatory infertility

OBJECTIVE: To evaluate the ability of a prediction model to identify the individual starting dose of FSH for ovulation induction using a step-down regimen. DESIGN: Retrospective analysis of clinical data in an academic fertility unit. Fifty-six normogonadotropic anovulatory infertile patients who failed to ovulate or conceive with clomiphene citrate were included. They were treated with exogenous gonadotropins with a flexible starting dose for ovulation induction using a step-down regimen. The clinically applied starting dose of exogenous gonadotropins was compared with the calculated response-dose using a previously published prediction model. RESULTS: Patients were arbitrarily divided into three groups according to the day of the first decrease in gonadotropin dose: (a) early step-down (day 3 or earlier); (b) standard step-down (day 4 or later); (c) no step-down. These groups had average starting doses of 28.5 IU (group a) and 13 IU (group b) above the calculated response-dose, and 43 IU (group c) under the calculated response-dose. A significant correlation between day of first step-down and the difference between clinically applied and calculated response-dose was observed (P<0.0001, F-test for ANOVA). CONCLUSIONS: The patient group with the best step-down profile for ovulation induction exhibited the closest match between the clinically applied and calculated starting dose of gonadotropins. Therefore, this study provides support for the concept that the individual effective FSH starting dose for gonadotropin induction of ovulation in anovulatory infertile patients can be predicted on the basis of initial screening characteristics, such as body mass index, clomiphene resistance or failure, free IGF-I and FSH. This may result in more effective patient treatment protocols, reduced complication rates and health-economic benefits.