At 16 weeks’ gestation, the fetus is about 16 centimeters in length, 12 centimeters in parietal length, and weighs about 110 g. Facial organs, such as the eyes, ears, nose, and mouth, can be distinguished, and the limbs are more mature and mobile. The scalp has grown hair, and the fetus has begun to show respiratory movements that can move amniotic fluid in and out of the respiratory tract. The external genitalia of the fetus in the 16th week of pregnancy have completed gender differentiation, and the gender of the fetus can be confirmed from the external genitalia through ultrasound. At 16 weeks of gestation, the skin of the fetus is thin and dark red, and there is no subcutaneous fat. In the 16th week of pregnancy, fetal gastrointestinal function is basically established, and the fetus can swallow amniotic fluid and absorb water, amino acids, glucose and other soluble nutrients to promote fetal growth and development. At 16 weeks of pregnancy, the fetus is in the stage of growth and maturity, pregnant women should go to the hospital on time for pregnancy checkups, and should go to the hospital in time when they find abnormalities in the growth and development of the fetus in the uterus, so as to avoid affecting the safety and security of the fetus and the pregnant women.