Premenstrual dysphoric disorder (PMDD) is a much more severe form of premenstrual syndrome (PMS). It may affect women who are able to get pregnant. It’s a severe and chronic medical condition that needs attention and treatment. Lifestyle changes and sometimes medicines can help manage symptoms.

The tissue that lines the uterus is called the endometrium. Normally, if a woman doesn’t get pregnant, this tissue is shed each month during her period. In endometriosis, tissue that looks and acts like endometrial tissue implants outside the uterus.This can cause pain, heavy periods, and infertility.