A new strategy to determine ovarian reserve: antimullerian hormone testing

This short article reviews a new available blood test used to assess ovarian reserve in women considering fertility treatments: Antimullerian hormone (AMH) testing. 

Ovarian reserve refers to the amount of eggs remaining in the ovaries at a given time. Assessment of ovarian reserve is very important in guiding fertility treatment decisions. Women with a low ovarian reserve may wish to pursue treatment earlier. On the other hand, very high ovarian reserve may increase the risk of ovarian hyperstimulation syndrome (OHSS) – a dangerous condition which can occur while undergoing treatments to induce ovulation. Ovarian reserve may dictate the treatment choice in most infertility cases.

Currently, ovarian reserve is assessed by measuring basal FSH and estradiol levels – two hormones involved in regulating the ovulation cycles. Elevated FSH levels suggest there is a limited ovarian reserve.

Antimullerian hormone (AMH) is a hormone secreted by ovarian follicles (cyst-like structures that contain the eggs), thus its level is directly related to the egg supply in the ovaries (in contrast to FSH which is secreted by the pituitary gland in the brain). 

The authors outlined the reasons for implementing AMH testing instead of, or in addition to FSH testing to guide fertility treatment decisions. AMH has a constant level throughout the menstrual period, unlike basal FSH which has to be measured at a specific time. AMH is a better predictor of ovarian reserve than basal FSH and can also identify cases in which the ovarian reserve is high (with increased risk of OHSS).

Clinically, an AMH level below 0.5 ng/mL is associated with a very low ovarian reserve. In such cases, aggressive fertility treatments are recommended. Levels under 1 ng/mL suggest there is a limited ovarian supply which translates into a short window of opportunity for conception. Patients with AMH levels between 1-3.5 ng/mL are candidates for first-line treatments to induce ovulation. AMH levels over 3.5 ng/mL are associated with a high ovarian reserve, with a higher risk of developing OHSS during treatment.

AMH testing has its limitations, notably the inability to predict the "quality" of eggs. Even women with a limited ovarian supply may have a few eggs that fertilize easily and yield successful pregnancies. In older women with a high ovarian reserve, genetic testing of the eggs is recommended to exclude those with abnormalities. AMH levels below 0.5 ng/mL should also prompt basal FSH measurements, since at this level, the standard FSH test offers more information.

AMH testing is very useful in assessing ovarian reserve and guiding fertility treatment decisions.

If you consider an assisted reproductive treatment, ask your doctor about the availability of the antimullerian hormone (AMH) test.