A review of hormonal changes during the menopausal transition: Focus on findings from the Melbourne Women's Midlife Health Project

Abstract

The menopause, defined as the permanent cessation of menstruation resulting from the loss of ovarian follicular activity, marks the end of natural female reproductive life. It is preceded by a period of menstrual cycle irregularity, the menopausal transition, which usually begins in the mid-40s and is conventionally divided into early and late phases. The endocrine changes, which underlie the transition, are predominantly the consequence of a marked decline in ovarian follicle numbers. The most significant changes include a decrease in early cycle inhibin B and in anti-Mullerian hormone (AMH) levels. The decline in inhibin B results in an increase in FSH, which appears to be an important fac..