Pregnant women in their fourth month of pregnancy have no special requirements for sleeping posture, subject to comfort. In the fourth month of pregnancy, the fetus is small, there is no obvious pressure on the pelvic organs and major blood vessels, it will not affect the blood circulation of the pelvic blood vessels, and it will not affect the blood supply of the fetus, so the specific sleeping position is not restricted, you can lie on your side, or you can lie down in the flat position, and you can sleep however comfortable you want. In late pregnancy, that is, after seven months of pregnancy, the fetus and the uterus increase in size, if you take a long time lying down position, the pelvic organs and abdominopelvic blood vessels of the compression effect increased significantly, affecting the mother and the fetus’s blood supply and oxygen supply, which may lead to the mother’s heart attack, chest tightness and other symptoms of discomfort. If the side lying position is taken, the compression effect is obviously reduced, and the chances of adverse effects will be significantly reduced. Although there is no restriction on the sleeping position in the 4th month of pregnancy, you should also pay attention to rest, strengthen the influence, and carry out regular maternity checkups. If you are self-conscious of any discomfort, you should go to the hospital in time.