The uterus of a pregnant woman in the 16th week of pregnancy is obviously enlarged and has exceeded the pelvis, the abdomen is visible bulging, and the uterine bottom is between the umbilicus and the umbilicus and the shame when the pregnant woman is lying down. At this time, the fetus is about 16cm in length, 12cm in parietal length, and weighs about 110g. At 16 weeks of pregnancy, the pregnant woman has reached the middle stage of pregnancy. With the growth of the fetus, the uterus is also gradually enlarged, and the bottom of the uterus can be touched between the umbilicus and the umbilicus when the pregnant woman is lying down during the labor examination. At this time, the fetus weighs about 110g, the scalp has grown hair, and the fetus has begun to breathe and move. The skin is thin and dark red and there is no subcutaneous fat. At 16 weeks of pregnancy, some pregnant women are aware of fetal movement and can monitor the condition of the fetus in the uterus through fetal movement. At this time, Down’s syndrome screening or non-invasive DNA can also be performed to detect chromosomal abnormalities in the fetus. Pregnant women should do regular obstetric examination to observe the development of the fetus.