Menstrual disturbances

Abstract

An understanding of the sequence of events that occur in a normal menstrual cycle is necessary for the management of menstrual disturbances. The hypothalamus secretes gonadotropin-releasing hormone (GnRH) in a pulsatile manner that stimulates the pituitary to release follicle-stimulating hormone (FSH) and luteinising hormone (LH). The co-ordination of these trophic hormones stimulates the ovary to develop a cohort of follicles, selects the dominant Graafian follicle which secretes oestrogen in the follicular phase, releases an oocyte in response to the LH/FSH surge (ovulation) and then forms the corpus luteum that secretes progesterone. The lifespan of the corpus luteum is about 14 days if implantation does not occur. The ovarian steroid hormones (oestradiol and progesterone) provide feedback to the hypothalamus and pituitary to prepare for the next menstrual cycle. Changes in any portion of the hypothalamic-pituitary-ovarian (HPO) axis can lead to menstrual cycle disturbances.