To a sleep-deprived new mother, waking a peacefully snoozing infant seems almost sacrilegious -- and, in fact, it may be unnecessary. As long as your newborn baby nurses at least eight times in 24 hours, regains her birth weight by 2 weeks, and continues to gain 4 to 7 ounces a week, you don't have to wake her to nurse. (By 4 months, most babies' bellies have developed to hold enough food so they don't require middle-of-the-night feedings anymore.)
On the other hand, if you're worried that she's not gaining enough weight, don't let her sleep through feedings, even if you have to set an alarm to wake yourself up. Inadequate calories can weaken a baby and make her sleep instead of cry, which can turn into a vicious circle of more sleepiness and insufficient feedings. --Katy Koontz
Originally published in Parents magazine, August 1999. Updated 2009.