Birth Control Pills and Ovarian Reserve Indicators – Important Information!
The most common tests for evaluation of ovarian aging (ovarian reserve) are the cycle day three follicle stimulating hormone (FSH) and estradiol (E2) levels, antimullerian hormone level (AMH), and the follicle count (antral follicle count). The results of these tests have important implications with regard to choice of treatment and potential for success. A recent Danish study shed some important light on how birth control pills may alter two of these indictors, the AMH level and the antral follicle count, leading to an erroneous conclusion of diminished ovarian reserve. In this study, women taking the pill had 19% lower levels of AMH, and had 16% fewer antral follicles. The birth control pill temporarily reduces the volume of the ovary because it suppresses pituitary stimulation of the ovaries. Once oral contraceptives are discontinued, full pituitary control of the ovaries returns and AMH levels and antral follicle counts return to normal. There was no indication that the pill had any adverse effect on fertility.
Physicians must be aware of this temporary effect of birth control pills on ovarian reserve markers, and postpone assessment of AMH and antral follicle count until patients are no longer taking oral contraceptives. The results of the study do not imply that the pill prematurely ages women’s eggs. Instead, the findings suggest that the pill obscures a woman’s underlying reproductive status.