My Baby This Week: 12 Weeks

The most dramatic development this week: Reflexes. Your baby's fingers will soon begin to open and close, his toes will curl, his eye muscles will clench, and his mouth will make sucking movements. In fact, if you prod your abdomen, your baby will squirm in response, although you won't be able to feel it. His intestines, which have grown so fast that they protrude into the umbilical cord, will start to move into his abdominal cavity about now, and his kidneys will begin excreting urine into his bladder. From crown to rump, your baby-to-be is just over two inches long (about the size of a lime) and weighs half an ounce.