The abdominal circumference at 12 weeks’ gestation usually does not change significantly, and the enlarged uterus can be palpated by palpation 2-3 transverse fingers above the pubic symphysis. The belly usually increases in size at about 16 weeks of pregnancy. At 12 weeks of pregnancy, the uterus is three times the size of a non-pregnant uterus, and the uterus can rise slightly above the pubic symphysis, and the enlarged uterus can be palpated by a medical professional. As the embryo and uterus are still small, the abdominal circumference of most pregnant women does not increase significantly. If a pregnant woman does not control her diet and overeats after the initial pregnancy, her belly will also appear to increase in the 12th week of pregnancy, but all of them are the pregnant woman’s own weight, not the belly enlargement caused by the increase in the weight of the fetus. If the belly of the twelfth week of pregnancy appears to be obviously enlarged, vaginal bleeding and abdominal pain, need to cause alarm, go to the hospital in a timely manner to accept the relevant examination, to avoid the occurrence of serious consequences.