The pain in the small abdomen that occurs more than 20 days after menstruation is considered to be caused by uterine contractions, because the uterus can return to its normal form only after 42 days after delivery. It is a normal physiological phenomenon. If the pain persists for more than 2 days, you need to go to the hospital for an ultrasound to determine if there is a certain amount of fluid in the pelvic cavity or if there is a cystic torsion. It is important to remind that because some women have cysts during pregnancy that are not removed during delivery, it is not advisable to observe the pain at this time and go to the hospital at any time for an examination, as it is necessary to exclude the presence of torsion and rupture.