Empty follicle syndrome: An entity in the etiology of infertility of unknown origin, or a phenomenon associated with purified follicle-stimulating hormone therapy?

Most in vitro fertilization (IVF) programs use mainly stimulated cycles for better recovery from the supportive cohort of follicles. The regimens for ovulation induction in IVF include clomiphene citrate (CC) and human chorionic gonadotropin (hCG), human menopausal gonadotropin (hMG), hMG/hCG, and CC with hMG/hCG. Newer methods using pure follicle-stimulating hormone (FSH), (Urofollitrophin [FSH], Serono Laboratories, Inc., Randolph, MA) alone or pure FSH with hMG/hCG have been applied. This medication is only a recent addition to our armamentarium, and an understanding of its use and side effects is still evolving. We report a rather infrequent finding in four women treated with purified FSH in our IVF unit.