At 16 weeks’ gestation, the baby is about 10-15 centimeters long and is gradually gaining weight. The fingers, toes and nose of the fetus can be seen more clearly through ultrasound, but the head is still large compared to the torso. At this stage, the baby’s external genital differentiation is gradually completed, the hair on the scalp appears to grow, and some fetuses are able to carry out intrauterine activities. At 16 weeks’ gestation, the baby’s head develops obviously, and the skin on the body surface is thin and transparent, and the blood vessels under the skin can be seen more clearly. At this stage, the joints of the limbs are gradually forming, the bones are developing, and the nails are completing their development. At this time, the baby’s eyelids have been formed, but still in the closed state, can be seen brown fat protective layer, can be observed breathing movement. The development of the baby in the 16th week of pregnancy is relatively stable, but pregnant women still need to do regular checkups in order to understand the growth of the fetus, and if there is any abnormality, they should go to the hospital in time for examination, and carry out targeted treatment as early as possible.