Objective: To validate a published model for the prediction of the individual FSH response dose for gonadotropin induction of ovulation in polycystic ovary syndrome (PCOS).
Design: Structured, complete, and carefully monitored patient-based data collection to test the external validity of the prediction model.
Setting: Twenty-nine hospitals in The Netherlands.
Patient(s): Eighty-five clomiphene citrate (CC)-resistant women with PCOS.
Intervention(s): Ovulation induction in a chronic low-dose step-up FSH regimen.
Main outcome measure(s): Predicted individual FSH response dose, defined as follicle growth >10 mm in diameter on ultrasound.
Result(s): The model, using the women's body mass index, CC response, initial serum FSH level, and initial serum insulin-to-glucose ratio was studied in the validation sample. Overall, the FSH response dose predicted by the model was higher than the observed response dose. The predictive performance of the model was poor, with an R(2) of 0.11, and the average prediction error was 35 IU.
Conclusion(s): The external validity of the model predicting the individual FSH response dose was inadequate in women with CC-resistant PCOS undergoing ovulation induction with recombinant FSH in a low-dose step-up regimen.