The first cause of headache before menstruation is vascular headache. Some women have headache before menstruation because there is a female hormone called primordial follicle hormone, which regulates the tension of blood vessels. When menstruation is due, the secretion of female hormones decreases sharply, resulting in an unstable state of female blood vessels, which can cause headaches. The second reason is because the ratio of estrogen to progesterone is out of balance, which can cause headaches. When estrogen drops to a certain level, it will trigger headaches. Moreover, the level of estrogen fluctuates up and down with the change of menstrual cycle, so it causes more women in clinical practice to have cyclic headaches during their menstrual cycle.