Menstrual irregularities and the perimenopause

The perimenopause is defined as the phase of women's reproductive life between the time when cycles change and become irregular until menopause. Compared with younger women, follicle-stimulating hormone is elevated. In ovulatory cycles, luteal insufficiency frequently occurs. Estrogen secretion is elevated throughout the menstrual cycle during some phases of the perimenopause. Perimenopausal women are deficient in the hypothalamic-pituitary estrogen positive feedback mechanism on luteinizing hormone (LH) secretion. We challenged young and perimenopausal women with earlier follicular-phase estrogen boluses to attempt to induce LH surges. Whereas six of eight young women exhibited surges, only one of eight perimenopausal women had a surge of LH to estrogen challenge. Thus, perimenopausal changes involve mechanisms other than ovarian hypofunction. Complex central nervous system mechanistic changes also occur. A better understanding of the physiology in control mechanisms should allow for better symptom management of the perimenopause.