Your baby is growing rapidly now. This week he weighs about 2 1/2 pounds (about the size of a butternut squash) and is a tad over 15 inches long from head to heel. His muscles and lungs are continuing to mature, and his head is getting bigger to accommodate his growing brain – which is busy developing billions of neurons. Every day, about 200 milligrams of calcium is deposited in your baby's skeleton, which is now hardening....
