RESUMO
OBJECTIVE: The objectives of this study were to clarify changes in antimüllerian hormone (AMH) concentrations during the menopausal transition and to determine whether AMH may serve as a marker to predict the onset of menopause. METHODS: Blood samples were collected annually for 6 years from 595 women living in Iwaki, Japan. We selected 44 women according to strict criteria: those older than 40 years at first participation; those who had their regular menstruation; those whose menstrual cycle had changed from regular to irregular or those who met the final menstrual period; and those who did not take medication that may affect the menstrual cycle. Serum AMH concentrations were determined by the newly developed AMH Gen II assay kit. Stage of the menopausal transition was defined according to the Stages of Reproductive Aging Workshop. RESULTS: Among the 44 women who participated in the study, 29 experienced menopause during the study (group A), whereas the remainder developed irregular menstrual cycles (group B). AMH was consistently found to be undetectable for 3 years before menopause, suggesting that AMH is a sensitive marker for predicting the onset of menopause. In addition, serum AMH was detectable at low levels in women from group B until menstrual cycles became irregular, suggesting that AMH serves as a marker for diagnosing the menopausal transition. CONCLUSIONS: When AMH levels fall below detectable levels, women at the menopausal transition will progress to menopause within 3 years.