Generally in the fourth month of pregnancy, the phenomenon of pregnancy will appear, from the surface can be seen in the belly bulge, small abdominal protrusion forward, walking posture will also change, at this time the amount of amniotic fluid has an impact on the situation of pregnancy, or the abdominal wall relaxation, pregnant women obese body, will also show more obvious phenomenon of pregnancy. If the woman is in labor and has a loose belly, it will also be more obvious. If it is a primiparous woman or if the abdominal wall is tense and the amniotic fluid volume is relatively small, it will not be particularly obvious at this time, and it is only as the pregnancy week increases that the belly will obviously have a protruding phenomenon. In the fourth month of pregnancy, you should pay attention to review the uterine height and abdominal circumference, and you should also pay attention to ultrasound to check the development of the fetus.