Samantha F. Butts, MD, MSCE Dr. Butts is Assistant Professor of Obstetrics and Gynecology, Division of Infertility and Reproductive Endocrinology, at University of Pennsylvania Medical School in Philadelphia.
David B. Seifer, MD Dr. Seifer is Co-Director of Genesis Fertility and Reproductive Medicine at Maimonides Medical Center in Brooklyn, NY, and Professor of Obstetrics, Gynecology and Reproductive Sciences at Mount Sinai School of Medicine in New York City.
In a recent series investigating AMH levels in women with PCOS, AMH and the degree of insulin resistance were positively correlated, and the AMH level was negatively correlated with the number of menses in a year.49 The consistently positive correlation between AMH and PCOS may suggest a future role for this marker as a diagnostic tool.
In obese women who do not have PCOS, AMH production may be lower than in women of normal weight. In a recent series, normally cycling obese women in the later reproductive years were shown to have an AMH level 70% lower than those in women who were not obese.54 These differences have not been well studied in younger obese women.
Which test is best?
AMH may be preferable to the other tests to assess ovarian reserve because it can be measured any time during the menstrual cycle or between cycles. AMH measurement is also useful if a woman is taking oral contraceptives or leuprolide acetate because these medications may confound the results of the other test methods. In addition, AMH may be the earliest indicator of decline in ovarian reproductive function. As such, it may highlight cases that merit a search for other causes of infertility and make it possible to treat them in a timely manner.
Elevated AMH may reveal occult PCOS and warn of significant risk of ovarian hyperstimulation prior to ovulation induction with gonadotrophins, so that the clinician can plan smaller doses.
Ovarian reserve declines with age, but not uniformly
A normal female is born with 1 million to 2 million oocytes, a number that declines continuously, primarily through the process of follicular atresia. By the onset of puberty, the number of oocytes has declined to approximately 300,000. As a woman enters her late 30s, when the total number of oocytes is approximately 25,000, the pace of oocyte depletion begins to increase, as does the rate of spontaneous miscarriage.1,55,56
The effect of age on fertility is believed to arise from changes in both oocyte number and quality. Multiple investigators have found a greater frequency of cellular abnormalities in oocytes from older women.1,2,5,15,57
Although ovarian reserve declines with age in all women, women of similar ages can have very different degrees of ovarian reserve, and some women who have very poor ovarian reserve may never conceive, despite aggressive fertility treatment.
The biologic basis for differences in ovarian reserve among similar groups of women is not completely understood, but is probably rooted in genetic, lifestyle, and environmental factors that affect granulosa cell and oocyte function. Identifying sensitive biomarkers that can determine ovarian reserve independent of age is critical to predict fertility and age at menopause.5
