In reproductive medicine, there are few, if any, more pressing concerns from our patients than the biological clock, i.e., ovarian aging. While addressing this issue with women can be challenging, particularly for those who are anxious regarding their advanced maternal age, gynecologists must possess a thorough understanding of available diagnostic testing. This article will review the various methods to assess ovarian age and appropriate clinical management.
Dr. Mark P. Trolice
Ovarian reserve tests
Ovarian reserve represents the quality and quantity of oocytes. The former is defined by the woman’s chronologic age, which is the greatest predictor of fertility. From a peak monthly fecundity rate at age 30 of approximately 20%, the slow and steady decline of fertility ensues. Quantity represents the number of oocytes remaining from the original cohort.
Ovarian reserve is most provocatively gauged by the follicle response to gonadotropin stimulation, typically during an in vitro fertilization (IVF) cycle.
Several biomarkers have been used to assess ovarian age. These include FSH, estradiol, and inhibin B. In general, these tests are more specific than sensitive, i.e., “normal” results do not necessarily exclude decreased ovarian reserve. But as a screening tool for decreased ovarian reserve, the most important factor is the positive predictive value (PPV). Statistically, in a population of women at low risk for decreased ovarian reserve, the PPV will be low despite sensitivity and specificity.
While inhibin B is a more direct and earlier reflection of ovarian function produced by granulose cells, assays lacked consistent results and a standardized cut-off value. FSH is the last biomarker to be affected by decreased ovarian reserve so elevations reflect more “end-stage” ovarian aging.
Additional tests for decreased ovarian reserve include antral follicle count (AFC) and the clomiphene citrate challenge test (CCCT). AFC is determined by using transvaginal ultrasound to count the number of follicular cysts in the 2- to 9-mm range. While AFC can be performed on any day of the cycle, the ovary is most optimally measured on menses because of less cystic activity. A combined AFC of 3-6 is considered severe decreased ovarian reserve. The CCCT involves prescribing clomiphene citrate 100 mg daily from cycle day 5-9 to measure FSH on cycle days 3 and 10. An FSH level greater than 10 IU/L or any elevation in FSH following CCCT is considered decreased ovarian reserve.
FSH had been the standard but levels may dramatically change monthly, making testing only valuable if it is elevated. Consequently, antimüllerian hormone (AMH) and AFC are considered the most useful tools to determine decreased ovarian reserve because of less variability. The other distinct advantage is the ability to obtain AMH any day in the menstrual cycle. Recently, in women undergoing IVF, AMH was superior to FSH in predicting live birth, particularly when their values were discordant (J Ovarian Res. 2018;11:60). While there is no established consensus, the ideal interval for repeating AMH appears to be approximately 3 months (Obstet Gynecol 2016;127:65S-6S).