Tightening of the stomach all the time during pregnancy may be a sign of false uterine contractions and preterm labor. 1. False uterine contractions: in late pregnancy, if the pregnant woman is in a prolonged period of excessive tension and fatigue, doing body flexion or pressure on the abdomen, the fetus in the uterus frequent activities, false uterine contractions may occur, the contractions are not regular, the duration of a short period of time, abdominal tightness, hardness of the symptoms. 2. Prolonged labor: the late pregnancy stomach has been tight to consider the manifestation of prolonged labor, the stomach appears tight, accompanied by paroxysmal pain, and regularity, the pain interval gradually shorten, the pain time gradually prolonged, this is the contractions caused by prolonged labor. If you have a tight stomach during pregnancy, you need to go to the hospital in time to find out the cause and ensure the safety of the mother and child.