One of the greatest challenges faced by practicing clinicians is to determine where individual patients are in the process of depleting their reproductive potential. To address this question, a number of different tests have been proposed (Basal FSH (Follicle Stimulating Hormone), Clomiphene Citrate Challenge Test, Anti-Mullerian Hormone (AMH), Basal Antral Follicle Count, etc…). Probably the most commonly used test is the basal FSH (follicle stimulation hormone) testing. The premise of the test is that the early follicular FSH peak reflects ovarian sensitivity to gonadotropin stimulation, which in turn correlates with the quality of the oocytes that are produced. Early studies consistently demonstrated that delivery rates declined steadily with increasing basal FSH levels. This led to utilization of basal FSH screening as a means of assessing ovarian reserve and counseling patients about their reproductive potential prior to undergoing treatment.
Recently, a number of reports have questioned the utility of basal FSH screening and urging caution when counseling patients using this test. As the literature has expanded, incredibly disparate conclusions have been presented. Some studies continue to demonstrate the predictive value of basal FSH while others indicate little if any association with clinical outcome.
A critical review of this controversy reveals that investigators used widely disparate methods for determining the threshold that would be considered normal versus those that are considered to be elevated. Methods for determining a threshold value of serum FSH that predicts IVF success have included the upper limit of normal reported by the manufacturer of the assay system, the upper limit of confidence intervals from various populations, receiver operator characteristic (ROC) curves and seemingly arbitrary threshold value. The threshold selected to separate normal from abnormal is of critical importance for any screening test. Basal FSH screening to assess ovarian reserve is no exception.