The document summarizes fetal development over the three trimesters of pregnancy. In the first trimester, the ovum and sperm combine and the placenta and external and internal features begin to form. By 12 weeks, the fetus shows reflexes and its face is recognizably human. In the second trimester, rapid growth and development occurs and movement is felt by 24 weeks when the circulatory and digestive systems are developed. In the third trimester, rapid brain development happens and internal organs mature, while by 40 weeks the fetus weighs around 7 1/2 pounds and is ready for delivery, having developed fat and positioned head-down in the birth canal.