Don’t even remember what it’s like to sleep a full night without a hazy trip to the nursery? The key to ending those dreaded nighttime wails is getting to the bottom of why they’re happening. Here are five reasons babies wake and what to do about them.

—Baby is too hot or too cold

Baby’s pretty sensitive to her environment, so adjust your thermostat to a sleep-friendly temp — for baby, that’s 68 to 72 degrees Fahrenheit, says Nanci Yuan, MD, medical director of the Sleep Center at Lucile Packard Children’s Hospital Stanford. Also, beware of overheating her with a ton of layers. Baby doesn’t need to sleep in a hat, and he doesn’t need more than a sleeper and a sleep sack.

—Baby is uncomfortable

Too tight pajamas, a hair wrapped around a toe (it happens!), a leaky diaper — there are all sorts of things that can cause baby discomfort throughout the night. And some babies are more sensitive than others. Check baby for potential irritants, like the hair or a rough snap on her sleeper, before bedtime.

If baby wakes because of a middle-of-the-night blowout, Yuan says to keep the diaper change “all business.” Don’t turn on many lights, talk too much or play with baby. Set the precedent that this isn’t time for fun — it’s time to get back to sleep.

—There’s too much light

Invest in blackout curtains, suggests Yuan, since even the glow from the streetlights outside could be too much for baby. Baby’s too young to be scared of the dark, so she really doesn’t need a nightlight. Of course, you might need one you can turn on, so you don’t trip when you’re in there.

—Baby wants to eat

Newborns need to feed around the clock and gradually start to eat the bulk of their meals during the daytime. Still, for some babies, waking for a nighttime feeding can be a tough habit to break. Paula Prezioso, MD, of the Pediatric Associates of NYC, says babies as young as four months old can go all night without feeding. During the day, follow an “eat-wake-sleep” routine that includes plenty of “eat,” so baby’s getting her nutrition during the daytime, Prezioso says. But remember: Feedings can also be very bonding, so baby might not be in it just for the breast milk or formula — she might be waking for you. Which brings us to our next point…

—Baby misses you

Separation anxiety often sets in around four months, says Prezioso, and can mean crying every hour and a half or two hours just to get close to you. Ever heard of Dr. Spock or Dr. Ferber? Both doctors recommend sleep training baby to self-soothe. The strategy: Go to baby to reassure her when she cries out, but don’t take her out of the crib during the night. Try it for a few nights, each time increasing the amount of time you wait before you go into the nursery.

“It’s essential that babies learn how to self-soothe and fall back asleep on their own without heroic measures,” says Yuan. “Good sleep habits now will ensure good sleep habits for life.”

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(For pregnancy and parenting advice, tools and more, visit TheBump.com.)