It’s 3 a.m. You’ve just managed to drift off after a long night of diaper changes and lullabies when your baby suddenly lets out a sharp cry from the crib. You rush over, only to find their eyes still shut, face relaxed, and body seemingly calm. Confused and sleep-deprived, you ask yourself— why do babies cry in their sleep?

If you are a first-time mom or even a seasoned one, it can be very unsettling to hear your baby cry while sleeping. You might think, “Is it a nightmare?” “Are they in pain?” “Do they need something?” Understanding the reasons behind this nighttime crying session can help moms deal with it better. So, mommies, are you ready for it? Let’s get started!

Why do babies cry in their sleep?

• Newborns and infants experience very different sleep patterns from adults. While grown-ups spend most of the night in deep, restorative sleep, babies have shorter sleep cycles. During REM (Rapid Eye Movement), a baby might twitch, whimper, or even let out a sudden cry. This doesn’t necessarily mean they’re in distress. It’s just a sign that their brain is developing.

• If you’ve ever seen a baby suddenly throw out their arms and cry while sleeping, you’ve witnessed the Moro reflex. It can be triggered by a loud sound, a sudden movement, or even a sense of falling during sleep. The reaction can startle the baby enough to cause a brief cry, even if they don’t fully wake up.

• Babies are sensitive to discomfort. They may cry in their sleep if they have gas, feel too hot or cold, feel hungry or even when they are teething. 

• As babies grow and become more aware of their surroundings, they start to develop separation anxiety. If they briefly stir in their sleep and don’t see or feel a familiar presence (like mom or dad), they might cry, even while half-asleep.

What amount of crying is normal?

It is normal for newborns (0–3 months) to cry for about 1 to 3 hours a day, often spread out over short bursts. By 3–6 months, babies are starting to sleep for longer stretches, but they still wake frequently. Occasional baby crying in sleep is still very common. As babies develop more predictable sleep routines, baby crying in sleep may decrease, but emotional development, teething, and growth spurts can trigger nighttime fussiness.

Hearing your baby cry in their sleep can tug at your heart and mess with your already fragile sleep schedule. But you should know that it is not that you are doing something wrong. Baby crying in sleep is the natural part of baby growth, and every parent has to go through it. The best thing you can do is to learn the reasons behind crying. If discomfort is the reason behind their crying while asleep, switch their bedding to a comfort wrapper or baby sleeping bag that is soft and provides enough comfort. This little change can bring them to ease, and you’ll both find your rhythm—and sleep will come again!