Abstract
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 1st 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% to 96.3%) of the participants in this study. The median serum AMH concentration was 10.9 pmol/L in the 1st trimester and 6.5 pmol/L during the 2nd trimester, with a significantly different distribution of the values between the 1st and the 2nd 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 1st to the 2nd trimester of pregnancy. The absolute decrease in AMH levels seems to be positively associated with 1st trimester AMH levels, whereas the percentage of AMH difference is not. Further studies are required to elucidate the potential physiological mechanisms of this finding.