Ovarian reserve is a measure of the quantity and quality of the eggs; it is best measured by a combination of chronological age, antral follicle count (AFR) on ultrasound, and anti-mullerian hormone (AMH).
An AFR of less than 11 reflects diminished ovarian reserve and less than 6 is severe. AMH levels below 1.6 have been shown to reduce the number of eggs retrieved with IVF and may predict pregnancy outcome. Levels below 0.4 are severe.
Using a test to detect a low ovarian reserve in a low-risk population will result in a greater number of false-positive results (i.e. characterizing a woman with low ovarian reserve when she actually has a normal ovarian reserve). A recent article in JAMA showed no difference in natural pregnancy rates in women aged 30-44 years, regardless of HMA levels.
Very low levels of AMH (<=0.4) affect the outcome of IVF cycles. In 2016, a study on Fertility and Sterility, using SART data from a population of women with an average age of 39.4 years, the cycle cancellation was 54%; of all recovery attempts, oocytes were not obtained in 5.4% and no embryo transfer occurred in 25.1% of cycles; and the live birth rate per embryo transfer was 20.5% (9.5% at the beginning of the cycle and 16.3% at the puncture) from an average age of 36.8 years.