(For a description of the menstrual cycle, see Female Reproductive Endocrinology: Menstrual Cycle.)

Menstrual abnormalities include amenorrhea, dysfunctional uterine bleeding, dysmenorrhea, and premenstrual syndrome. Irregular or absent menses and nonmenstrual vaginal bleeding have many causes, but in women of reproductive age, pregnancy should always be suspected. Abnormal vaginal bleeding in nonpregnant women (see Symptoms of Gynecologic Disorders: Vaginal Bleeding) is evaluated differently from vaginal bleeding in pregnant women (see Symptoms During Pregnancy: Vaginal Bleeding During Early Pregnancy and see Symptoms During Pregnancy: Vaginal Bleeding During Late Pregnancy).

Last full review/revision August 2012 by JoAnn V. Pinkerton, MD