When Menstrual Periods Stop

Another cause of amenorrhea is an increased prolactin secretion by the pituitary gland. During pregnancy, the rise in blood pituitary levels is normal because prolactin exists to stimulate breastmilk production.

Women with high prolactin levels who are not pregnant may notice a milky discharge from the breasts. But not all women with high prolactin have this symptom. Their only symptom may be irregular or absent menstrual periods.

A high prolactin level could be caused by certain medications or a small growth in the pituitary gland called a pituitary adenoma.