The pain in the stomach after the birth of the second child may be the pain caused by uterine contraction. You can take reasonable pain medication under the guidance of a doctor, such as taking ibuprofen and other drugs, but you should not take this pain medication frequently. You can also apply hot compresses to the abdomen and massage more locally, which can relax the local muscles and improve the pain symptoms. When the pain is severe, acupuncture treatment is also needed, and acupuncture can be applied to Guan Yuan point, Foot San Li and other parts of the body, which can also relieve the pain phenomenon. Pay attention to the sleeping position, it is best not to lie flat will increase the pain, it is recommended to lie on your side and drink more brown sugar water, biochemical pellets and other drugs, can promote the discharge of intrauterine residues and relieve pain. Postpartum uterine contraction pain is in 3-5 days, at most not more than 7 days, if more than 7 days may be intrauterine infection caused by stomach pain, intrauterine infection need to take amoxicillin, ceftriaxone and other anti-inflammatory drugs.