Some women do not have menstruation because it is related to the pituitary gland. The reasons for not having menstruation can be physiological or pathological. Physiologic reasons, such as pregnancy, breastfeeding, menopause, these women do not menstruate, but it has no effect on the body, and has nothing to do with the pituitary gland. If a woman with normal menstrual cycles suddenly stops menstruating, amenorrhea is usually a possible cause. Causes of amenorrhea include hypothalamic amenorrhea, pituitary amenorrhea, ovarian amenorrhea, uterine amenorrhea, etc. Pituitary amenorrhea is closely related to the pituitary gland, and common causes include infarctions of the pituitary gland, such as Sheehan’s Syndrome, which is triggered by postpartum hemorrhage.