In a recent blog I had presented data which suggest that AMH levels in fact DO vary! AMH levels are also not supposed to be influenced by the use of birth control pills. A recent study from Finland suggests that this may not be true either.
Kallio et al. (Fertil Steril 2013;99:1305-1310) studied 42 healthy women over a period of nine weeks. Women had baseline blood hormone levels (AMH, Inhibin B, FSH, LH, E2) drawn and then were treated with oral contraceptives (13 women), patches (15 women) and vaginal ring (14 women) with blood levels evaluated at 5 and 9 weeks later. To cut a long story short – all 5 hormones including AMH were significantly suppressed at 9 weeks. AMH levels (ng/mL) were 3.88+3.0 at baseline, 3.34+2.8 at 5 weeks and 1.91+1.5 at 9 weeks. The suppression at 5 weeks, however, was not significant.
AMH is secreted by the (granulosa) cells surrounding growing follicles mainly up to 4-6 mm. The granulosa cell mass of these follicles is higher than in follicles in preceding phases and may contribute significantly to the overall secretion of AMH. Oral contraceptives reduce the effect of FSH and thus inhibit the growth of follicles, mainly in the antral stage (see illustration). In addition, the marked decline in serum AMH levels suggests that the continuous use of combined contraceptives inhibits the early phase of FSH-dependent follicular development and perhaps also to some extent follicular growth in preceding stages.
Should I Worry if My AMH is Low While on the Pill?
From a practical viewpoint, what does this mean? My previous blog on AMH level testing has attracted more than 100 questions. Some of these were from concerned young, healthy women who were not even trying to get pregnant and were on birth control pills. They had a random AMH level drawn, which turned out to be low. One was even advised by her (well meaning) gynecologist to pursue freezing her eggs as she was going to be menopausal soon!
This paper basically suggests that the low AMH level may have been secondary to oral contraceptive use – so, there is no need to worry! Programs screening potential anonymous egg donors may risk rejecting otherwise excellent donors if the AMH level is checked when the donor has been on oral contraceptives for a while.
Dr. Karande is Board Certified in the specialty of Obstetrics and Gynecology as well as the subspecialty of Reproductive Endocrinology and Infertility. He is a Fellow of the American College of Obstetricians and Gynecologists and Member of the American Society for Reproductive Medicine.