Adenomyosis occurs when the tissue that normally lines the uterus grows into the muscular wall of the uterus. The displaced tissue continues to act normally — thickening, breaking down and bleeding — during each menstrual cycle. An enlarged uterus and painful, heavy periods can result. Some symptoms include:
Heavy or prolonged menstrual bleeding
Severe cramping or sharp, knifelike pelvic pain during menstruation
Chronic pelvic pain
Painful intercourse