1. The size and development of the fetus at four months of pregnancy. At four months of pregnancy, the fetus has grown to about 14 centimeters and weighs about 100 grams. At this time, the fetus has a clear humanoid outline, and the head, body, limbs and other parts can be seen, and various organs have begun to mature. At this time, the development of the fetus can be observed through B-ultrasound examination. 2. The development of the fetus\’s nerves and sensory organs at four months of pregnancy. At four months of pregnancy, the fetus\’s nerves and sensory organs also begin to gradually develop. At this time, the fetus can already pass