An ideal test for assessing ovarian reserve should be noninvasive, analytically reliable, suitable for routine laboratory use, and should have a high clinical sensitivity and specificity. Basal serum levels of follicle stimulating hormone (FSH), estradiol, and inhibin have the advantage of being easy to determine. Of these, only FSH reflects a decline in fecundability reliably enough to be used a-s a screening assay. Tests for the assessment of reproductive capacity such as the clomiphene citrate challenge test, the GnRH challenge test, and the exogenous FSH challenge test have the advantage of being more sensitive for determining imminent ovarian failure. However, they are not suitable to be used in the general (infertility) population because of their invasiveness. Determination of FSH excretion in urine appears to be at least as reliable as basal serum FSH and has the advantage of being noninvasive. Therefore, it might be more suitable when screening larger numbers of patients. New developments include the interest in growth factors and hormones in follicular fluid. Measuring insulin-like growth factor in follicular fluid can be informative about the causes of a failed in vitro fertilization (IVF) treatment. During follicular growth, FSH acts as an inhibitor of apoptosis of granulosa cells, which is the main cause of follicular atresia. In imminent ovarian failure, an increased death of follicles caused by apoptosis (despite high levels of FSH) can be determined by measuring apoptosis in granulosa cells.