The
menstrual cycle is the regular natural change that occurs in the
uterus and
ovaries that make
pregnancy possible. The cycle is required for the production of ovocytes, and for the preparation of the uterus for
pregnancy. Up to 80% of women report having some symptoms during the one to two weeks prior to
menstruation. Common symptoms include
acne, tender breasts, bloating, feeling tired, irritability, and mood changes. These symptoms interfere with normal life and therefore qualify as
premenstrual syndrome in 20 to 30% of women. In 3 to 8%, they are severe.