23 Weeks

Turn on the radio and sway to the music. With his sense of movement well developed by now, your baby can feel you dance. And now that he's more than 11 inches long and weighs just over a pound (about as much as a large mango), you may be able to see him squirm underneath your clothes. Blood vessels in his lungs are developing to prepare for breathing, and the sounds that your baby's increasingly keen ears pick up are preparing him for entry into the outside world. Loud noises that become familiar now — such as your dog barking or the roar of the vacuum cleaner — probably won't faze him when he hears them outside the womb.