Decreased Ovarian Reserve (DOR)
Decreased ovarian reserve is a decrease in the quantity or quality of oocytes, leading to impaired fertility.
Ovarian reserve may begin to decrease at age 30 or even earlier and decreases rapidly after age 40. Ovarian lesions also decrease reserve. Although older age is a risk factor for decreased ovarian reserve, age and decreased ovarian reserve are each independent predictors of infertility and thus of a poorer response to fertility treatment.
Testing for decreased ovarian reserve is considered for women who
Measuring FSH or estradiol levels is useful as a screening test for decreased ovarian reserve. FSH levels > 10 mIU/mL or estradiol levels < 80 pg/mL on day 3 of the menstrual cycle suggest ovarian reserve is decreased. However, the AMH level and AFC are currently the best tests for diagnosing decreased ovarian reserve.
The AMH level is an early, reliable predictor of declining ovarian function. Increasingly, AMH measurement is used to assess ovarian reserve. A low AMH level predicts a lower chance of pregnancy after in vitro fertilization (IVF); pregnancy is rare when the level is too low to be detected.
The AFC is the total number of follicles that measure 2 to 10 mm (mean diameter) in both ovaries during the early follicular phase; AFC is determined by observation during transvaginal ultrasonography. If AFC is low (3 to 10), pregnancy after IVF is less likely.
Decreased ovarian reserve can also be measured using the clomiphene citrate challenge test; however, it is less reliable. For this test, the woman is given clomiphene 100 mg po once/day on days 5 to 9 of the menstrual cycle; then FSH and estradiol levels are measured again. A dramatic increase in FSH and estradiol levels from day 3 to day 10 of the cycle indicates decreased reserve.