Jaw-dropper: Your baby (like mine) may snooze an awful lot just after birth. But within days, she's liable to roar to life and say adiós to Ms. Mellow.

What it means: She's getting used to the world. Right after birth, your newborn is busy adjusting to the bright, stimulating environment outside your body -- a challenge that might make her super sleepy, says Linda Burk, M.D., a pediatrician in Blacksburg, Virginia. But after a few days with no placenta to nourish her, she'll grow too hungry to sleep so much. Plus, Dr. Burk adds, "you're probably helping her come out of her shell just by interacting with her."

Where do you go from here? Unless your baby is inconsolable, don't be alarmed. "After a while, you become tuned in to what she's demanding," says Richard Judelsohn, M.D., a pediatrician in Buffalo. "It's trial and error. If you feed her and she quiets down, you know that's her 'I'm hungry' noise." Soon you may also recognize her noises for "I'm tired," "I'm wet," and "I'm sick of being passed around like a bag of chips." Squalling is the price you pay to get in sync with her needs.