A majority of women experience menstrual periods that occur every 26-30 days on a regular basis. This regularity is the result of the ebb and flow of hormones produced by the hypothalamic area in the brain, the pituitary gland that lies at the base of the brain and the ovary. The hypothalamus secretes the hormone, gonadotropin releasing factor (GnRH) in bursts. In response, the pituitary gland secretes follicle stimulating hormone (FSH) and luteinizing hormone (LH). FSH and LH are transported in the blood stream to the ovary where both FSH and LH stimulate the maturation and release of one oocyte(egg) as well as stimulating the production of the major hormones of egg development, estrogen and progesterone.

Abnormalities of the hormones that control the menstrual cycle and/or abnormalities of the uterus itself can lead to irregular, absent or frequent menstrual periods. In order to successfully diagnose the cause of the abnormal menstrual periods, several tests may be suggested. The tests include measurements of all of the hormones that either directly or indirectly influence the secretion of FSH and LH by the pituitary gland as well as the hormones that are secreted by the ovary during normal or abnormal menstrual cycles. The evaluation also includes a physical examination of the cervix and uterus in addition to an ultrasound of the uterus to determine if the cause of the abnormal bleeding is the result of a structural problem of the uterus or uterine lining. Following the evaluation, an appointment is made to review and explain the results of the tests. Treatment of abnormal menstrual periods depends on the cause of the abnormality.