Age and basal follicle stimulating hormone as predictors of in vitro fertilisation outcome

Objective To examine the relative effect of basal follicle stimulating hormone (FSH) concentration and the woman's age on predicting the ovarian response to gonadotrophin stimulation, normal fertilisation rate and pregnancy rate in in vitro fertilisation (IVF) treatment following pituitary desensitisation. Design Descriptive cohort study. Participants Three hundred and forty-four women undergoing their first IVF cycle. Methods Basal (menstrual-day 3) FSH concentration was measured and the woman's age calculated before she underwent pituitary desensitisation followed by gonadotrophin ovarian stimulation and IVF treatment. Main outcome measures Cancellation rate due to poor ovarian response, total dose of gonadotrophin required to achieve follicular maturity, number of oocytes collected, normal fertilisation rate and pregnancy rate were compared between banded values of the variables studied. Results Increasing basal FSH concentration was associated significantly with increased cancellation rate, but increasing age was not. Both increasing basal FSH and age were associated significantly with increased total gonadotrophin dose, and reduced number of oocytes collected and pregnancy rate. Analysis of variance showed that the association for basal FSH with the number of oocytes was significant, independent of, and stronger than the effects of age. Logistic regression analysis showed that age, but not basal FSH, was independently associated with pregnancy rate. Neither basal FSH, nor age had significant association with normal fertilisation rate. Conclusion Basal FSH concentration is a better predictor of cancellation rate and of the number of oocytes collected in IVF treatment than age, but age is a stronger predictor of pregnancy rate.