There are two main reasons for abdominal pain in mid-pregnancy. First, the gradual increase in the size of the fetus, the uterus increases in size, pulling the ligaments or muscles to cause abdominal pain, this situation is physiological pain, no special treatment. Second, as the enlarged uterus presses on the intestines, it may lead to constipation, more stools accumulated in the intestines, and may induce contractions to appear premature labor, in this case, abdominal pain can occur, so pay attention to, usually pay attention to relieve constipation.