Newborns cry a lot, but they sleep even more. Most newborns sleep about eight to nine hours during the day and another eight hours at night, though not all at once. Your baby probably won’t sleep through the night (six to eight hours) until she’s at least three months old. Some babies don’t sleep through the night until six months or older. So it stands to reason that lots of crying starts up when you thought she was sleeping peacefully, or when you’re trying to sleep.

Crying is your baby’s primary way of sending you a message. Babies cry at night to signal that they are in need of your help. What’s she trying to tell you when she wakes up wailing or cries in her sleep? Here are the main reasons why babies cry at night, and what to try when you’re wondering how to stop a crying baby.

1. Routine Crying

This type of crying is usually attributed to disruptions in your baby’s normal schedule, and is rarely due to discomfort associated with a feeding issue. It may be time for your baby to eat or sleep, or your baby may be overstimulated.

What Helps: To soothe a baby crying at night, try cuddling, swaddling, and walking with your baby, all of which provide motion and body contact. A white-noise machine or fan in the room can help, too.

2. Sheer Hunger

Your newborn needs to eat every few hours because her stomach is so tiny. Most babies cry at night because they are hungry.

What Helps: Crying is actually a late indicator of hunger, after things like smacking lips or sucking on fist. Check the clock, and if it’s been two or three hours since the last feeding, your baby is probably waking up to tell you she needs to be fed.

3. Hunger-Gas-Crying Cycle

If your baby cries at night from hunger for some time, she may work herself into a frenzy and find it difficult to calm down when nourishment arrives. When a baby is frantic to eat, sometimes she then gulps air with the milk, causing gas. This can create a cycle of discomfort that makes your baby fuss and cry instead of settling back into sleep once her hunger has been satisfied.

What Helps: Feed your baby before she becomes frantically hungry. Taking a break to burp her during a feeding, as well as after, can help.

4. Crying Associated with an Allergy

When your baby’s crying is persistent and not related to hunger, sleep, or general discomfort, cow’s milk protein allergy may be the cause. Colic due to cow’s milk protein allergy tends to follow a pattern of threes: crying for more than three hours per day (usually in the evening), for more than three days per week, and for more than three weeks.

What Helps: You should consult your pediatrician to determine if your baby’s crying is the result of a cow’s milk protein allergy.

Although the stomach is your newborn’s main alarm clock right now, other things can cause baby crying at night. Check for:

• A diaper that needs changing
• A finger tangled uncomfortably in a swaddle
• A room that’s grown too hot or too cold
• Sickness (A baby who has a cold or ear infection might waken more often than usual.)

What Helps: Especially if you’ve just fed your baby and she’s still fussy, check out these other possibilities to learn how to stop a crying baby. A quick diaper change before feedings can make her feel calmer while eating. If you suspect sickness, check her temperature; a rectal temperature over 100.4°F (38°C) warrants a call to your pediatrician.