Serum anti-Müllerian hormone (AMH) concentration during pregnancy: a longitudinal study

A prospective longitudinal cohort study aimed to longitudinally examine the kinetics of anti-Müllerian hormone (AMH) during the first two trimesters of pregnancy. Pregnant women with stored first-trimester serum samples were recruited at 24–28 weeks gestation during their gestational diabetes testing, where they provided an additional serum sample. The samples were analysed for AMH, oestradiol and progesterone concentrations. A decrease in serum AMH was observed in 40 out of 45 (88.9%) (95% CI: 75.9–96.3%) of the participants in this study. The median serum AMH concentration was 10.9 pmol/L in the first trimester and 6.5 pmol/L during the second trimester, with a significantly different distribution of the values between the first-trimester and the second-trimester AMH samples (P < 0.001). The median percentage of AMH difference of −39.8%. This study demonstrated a significant decrease in serum AMH levels from the first to the second trimester of pregnancy. The absolute decrease in AMH levels seems to be positively associated with first-trimester AMH levels, whereas the percentage of AMH difference is not. Further studies are required to elucidate the potential physiological mechanisms of this finding. LAY SUMMARY: Anti-Müllerian hormone, also known as AMH, is produced by developing ovarian follicles in the ovary. The concentration of AMH in the serum is used as a marker of ovarian reserve. This marker has been shown to vary throughout the menstrual cycle and in women using hormonal contraception. This study examined this marker in women in the first and second trimesters of pregnancy to determine if it is variable throughout pregnancy. The study found that there was a significant decrease from the first to second trimester, with a larger decrease seen in women who had a higher first-trimester concentration of this marker. Further research is required to determine the physiological mechanism which causes the reduction of AMH in pregnancy.