There are three main causes of severe pain during childbirth: 1. Paroxysmal contraction of uterine muscles, which stretches or tears uterine muscle fibers, compresses uterine blood vessels, causes tissue ischemia and hypoxia, excites nerve endings, and generates electricity. The impulse is uploaded to the pain center of the brain, causing the mother to feel severe pain. 2. When the fetus passes through the birth canal, it compresses the birth canal, especially the lower segment of the uterus, cervix, vagina, and perineum, causing damage, traction, and pain. 3