Monthly cycle changes women’s brains

Activity in a brain region that regulates emotions fluctuates over the course of a woman’s menstrual cycle, according to a new brain-imaging study.

Up to half of all women experience a variety of emotional symptoms, such as mood swings, irritability, and depression, during the days leading up to their periods. Combined with physical complaints, including bloating and cramping, these symptoms are collectively called premenstrual syndrome (PMS).