Your baby's growing steadily, gaining about a quarter of a pound since last week. Since he's almost a foot long, that makes for a pretty lean figure, but his body's filling out proportionally. Your baby's brain is growing rapidly, and his taste buds may be working now. His lungs are developing "branches" of the respiratory "tree" and cells that produce surfactant, a substance that helps the air sacs inflate easily. Your baby can hear more now, and you may even notice her startle at loud, sudden noises. But he's probably getting used to the regular noises he hears around the house, such as your dog barking or the roar of a vacuum cleaner.