We investigated the serum anti-Mullerian hormone (AMH), oestrogen and progesterone levels in spontaneously conceiving pregnant women, diagnosed for hyperemesis gravidarum (HG), in the first trimester. Pregnant women admitted at Hospital between 5 and 12 gestational weeks and treated for HG were compared, in this prospective case–control study, to a control group. The serum AMH, oestradiol, and progesterone values of both groups were evaluated and compared, and potential correlations were calculated. The serum AMH values were significantly higher in the HG group than the control group (3.15 ± 1.51 ng/mL vs. 2.27 ± 1.20 ng/mL; p = 0.012). No significant difference in the two groups was about serum oestradiol and progesterone values (p = 0.264, p = 0.235). In the HG group, there was no significant correlation between AMH and oestradiol (p = 0.570). However, a significant positive correlation was determined between AMH and progesterone (p = 0.050). The area under the ROC curve (AUC) was 0.669 and the cut-off value was 2.65 ng/ml with sensitivity of 58.3% and specificity of 66.7% for AMH in pregnant women with HG. A correlation between AMH high values and unexplained HG was detected in spontaneous pregnancies in the first trimester. High AMH levels may play a role in HG etiopathogenesis, especially in pregnant women with low progesterone levels.

Impact statement
• What is already known on this subject? Aetiological causes of Hyperemesis gravidarum (HG) include hormonal, immunological, genetic, and psychological issues. However, no conclusive etiopathogenesis to explain the pathophysiological mechanism of HG has been stated.
• What do the results of this study add? Authors focussed on investigation a possible correlation between pregnant hormones and the HG pathogenesis, prevalent in the first trimester, when hormones are produced by either the placenta or corpus luteum. High anti-Mullerian hormone (AMH) levels may play a role in HG etiopathogenesis, especially in pregnant women with low progesterone levels.
• What are the implications of these findings for clinical practice and/or further research? A serum AMH level of ≥2.65 mg/mL could be predictive for the development of HG in the first trimester of a spontaneous pregnancy. Basing on these findings, more selective pharmacological treatments could be administrated to these patients.