16 weeks

@ 16 wks: Get ready for a growth spurt. In the next few weeks, your baby will double his weight and add inches to his length . Right now, he's about the size of an avocado: 4 1/2 inches long (head to rump) and 3 1/2 ounces. His legs are much more developed, his head is more erect than it has been, and his eyes have moved closer to the front of his head. His ears are close to their final position, too.