Background: When stimulating a patient with poor ovarian response for IVF, the maximal dose of gonadotropins injected is often determined by arbitrary standards rather than a measured response. The purpose of this study was to determine if serum FSH concentration during an IVF stimulation cycle reflects follicular utilization of FSH and whether serum FSH values may inform dose adjustments of exogenous FSH.
Methods: In this retrospective cross sectional study we studied 155 consecutive IVF cycles stimulated only with recombinant human FSH. We only included long GnRH agonist protocols in which endogenous FSH levels were suppressed. We correlated the serum concentration of cycle day (CD) 7 FSH with the number of oocytes retrieved, cleaving embryos and pregnancy rate.
Results: We found that a CD7 FSH concentration above 22 IU/L was associated with poor response regardless of the daily dose of FSH injected and a lower pregnancy rate.
Conclusions: We concluded that CD7 FSH concentration during stimulation could be used to guide FSH dosing in poor responders. If the CD7 FSH concentration is above 22 IU/L increasing the dose of FSH in an attempt to recruit more growing follicles is unlikely to be successful.