During pregnancy a series of changes occur in the systems and organs of the mother’s body, the most significant of which is the uterus. The mother’s body undergoes a great deal of change during pregnancy for the growth of the fetus. The uterus is the organ that undergoes the greatest changes during pregnancy. The uterus gradually increases in size from the time of conception to the end of pregnancy, when it is about 500 to 1,000 times larger than non-pregnant women and weighs about 20 times more than non-pregnant women. The blood flow to the uterus will also gradually increase to supply blood and oxygen to the fetus. The circulatory system also changes during pregnancy, with an increase in cardiac output and cardiac capacity compared to non-pregnancy. The respiratory system also undergoes changes that favor the supply of oxygen to the pregnant woman and the fetus. The metabolism of a pregnant woman also increases, requiring more energy consumption. Changes also occur in the digestive, urinary, and endocrine systems. Breasts will become bigger, areola will deepen and so on. The bones, joints and ligaments of the pregnant woman will also change to better accommodate the growth of the fetus and to prepare for delivery. All the major organs of the body will undergo changes after pregnancy, so it is important to monitor your pregnancy, go to the labor and delivery clinic on time, and consult a doctor if there is any abnormality.