A hard and tense stomach at 40 weeks of pregnancy is considered to be caused by uterine contractions. By 40 weeks of pregnancy, you are already in your due date and if this happens, you should first consider it to be a sign that your baby is about to be born. During this period, you should also pay attention to see if there is any bleeding. If there is redness, it means that the placenta in the uterus has separated from the endocervix and the capillaries have broken down, showing bleeding. The water may also break during this period, and the flow of amniotic fluid will stimulate the contraction of the uterus and promote the progress of the first stage of labor. If the fetal heart rate exceeds 160 beats or is below 120 beats, this indicates intrauterine hypoxia, and the pregnant woman should be given oxygen in time to avoid affecting the health of the fetus.