If a woman’s stomach doesn’t hurt when she has her period, but after giving birth to a child, she has pain in her stomach when she has her period, she needs to consider the following reasons: 1. Endometriosis, most commonly found in women who have had a cesarean section, in the process of having a cesarean section, if the endometrium is accidentally planted into the uterine incision or subcutaneous part of the abdomen, this will lead to regular, cyclical pain during menstruation. 2. The pain is caused by ectopic endometrial hyperplasia.2. Consider pelvic inflammation, if there is more serious pelvic stasis, pelvic blood accumulation, etc., and more serious gynecological inflammation, it may lead to stomach pain during menstruation.