Why is pregnancy hard?

During pregnancy, the uterus gradually enlarges. The uterus is composed of smooth muscle, which has contractile characteristics. Therefore, most pregnant women can feel uterine contractions from the beginning of pregnancy. In addition, when the fetus moves, the fetus hits the uterine wall, which can also induce uterine contractions. Therefore, the abdomen feels tight and hard. If the abdomen is hard and there is no pain, no more than ten times a day, this is a normal phenomenon and can be observed. However, if the abdomen begins to ache, and the frequency of abdominal hardness becomes more and more frequent, it may be a threatened abortion, and it is necessary to go to the hospital for examination and, if necessary, to protect the fetus.