Reproductive hormones: ageing and the perimenopause.

This review explores the pituitary-ovarian hormones involved with ageing and the onset of menopause. The serum patterns of pituitary-ovarian hormones throughout the menstrual cycle alter as menopause approaches. The increase in follicular phase FSH prior to menopause is attributed to an early decline in the ovarian hormone, inhibin B, which negatively regulates follicle-stimulating hormone (FSH) secretion. Serum inhibin B is believed to reflect the age-related decrease in ovarian follicle reserve, which is the primary source of serum inhibin B. The later rise in serum luteinizing hormone (LH) during the menopause transition is due to a cessation of ovarian follicle development. Hormonal patterns during the luteal phase of the menstrual cycle also show changes with age but these changes are poorly understood.