20 weeks of pregnancy is 4 months more than 20 days and is in the middle of pregnancy. At 20 weeks of pregnancy, the growth and development of the fetus begins to enter a rapid period. Fetal fat begins to appear on the skin of the fetus, and functions such as urination and swallowing gradually appear. At this stage, the fetus weighs about 320g and is about 25cm long, and the pregnant woman can obviously feel the fetal movement, but because of the small gestational weeks, the pattern of fetal movement has not been fully formed, and most of the time it is still in a sleep state. At this time, the uterus is obviously enlarged, and the bottom of the uterus can be detected at one finger below the umbilicus. Pregnant women in their 20th week of pregnancy need to pay attention to the timely supplementation of calcium, iron and other trace elements, calcium supplementation of not less than 600mg per day. reasonable diet, appropriate exercise, pay attention to weight control. Appointment of systematic ultrasound examination in time, before 20-24 weeks of pregnancy need to carry out the 1st big four-dimensional examination, screening malformation.