Why Is My Premature Baby So Sleepy?

If your babies were born early, you may feel like all they do is sleep.

Whether your premature babies are in the NICU, a special care nursery, or already home with you, it's common to notice they spend most of the day asleep. While it can be reassuring to see them resting peacefully, many parents wonder if they're sleeping too much.

The good news is that, in most cases, sleeping a lot is exactly what premature babies are supposed to do.

Sleep isn't simply downtime. It's one of the most important ways your babies' brains and bodies grow, heal, and mature after arriving earlier than expected.

💙 Twin Parent Tip

Don't worry if your babies sleep through much of the day. Quiet cuddles, talking softly, reading books, and skin-to-skin contact all help you bond, even when they're asleep.

Why Do Premature Babies Sleep So Much?

Babies born before 37 weeks still have important development left to do outside the womb.

Their bodies are working hard every minute to:

• Grow

• Build brain connections

• Learn how to feed efficiently

• Regulate body temperature

• Develop healthy sleep-wake cycles

• Strengthen their lungs and immune system

All of this requires energy.

Sleep allows premature babies to use that energy for growth instead of staying awake.

While full-term newborns also sleep a great deal, premature babies often need even more rest because they're still catching up on development that normally happens during the final weeks of pregnancy.

Sleep Helps Your Baby's Brain Develop

The last several weeks of pregnancy are a time of remarkable brain growth.

When babies arrive early, much of this development continues after birth.

During sleep, your baby's brain is:

• Forming new neural connections

• Processing sounds, touch, and other sensory experiences

• Organizing sleep patterns

• Supporting memory and learning

• Building the foundation for future development

Because sleep is so important, healthcare providers try to protect it whenever possible, especially for babies receiving hospital care.

Sleep Supports Growth and Healing

Growing takes a tremendous amount of energy.

Premature babies use calories for much more than simply gaining weight. They're also developing muscles, organs, bones, and immune systems.

Sleep supports:

• Healthy weight gain

• Tissue repair

• Muscle growth

• Immune function

• Hormone production

• Overall healing

Although it may seem like nothing is happening while your baby sleeps, their body is incredibly busy.

Why Does My Baby Seem So Hard to Wake?

Many premature babies sleep deeply and may not wake easily for cuddles or playtime.

This is usually because their nervous system is still maturing.

They may only wake briefly for:

• Feedings

• Diaper changes

• Medical care

• Short periods of alertness

As your babies grow and get closer to their original due date, you'll likely notice longer periods of wakefulness.

When Will My Premature Babies Stay Awake Longer?

Every baby develops at their own pace.

As your babies mature, you may notice:

• Longer awake periods

• More eye contact

• Increased movement

• More interest in feeding

• Greater awareness of voices and faces

• Longer stretches of interaction

These changes often happen gradually rather than overnight.

Is It Normal for Twins to Have Different Sleep Patterns?

Yes.

Twins may have different personalities from the very beginning.

One twin may:

• Wake more often

• Eat more eagerly

• Stay awake longer after feedings

• Sleep more deeply

• Reach developmental milestones sooner

These differences are common, especially in premature twins.

Healthcare providers evaluate each baby individually, even when they're twins.

If Your Premature Babies Are in the NICU

If your babies are receiving care in the NICU, you may notice that nurses try to avoid waking them unless necessary.

Many NICUs use clustered care, meaning routine tasks like diaper changes, feedings, assessments, and medications are grouped together whenever possible. This gives babies longer stretches of uninterrupted sleep, which supports healthy growth and brain development.

If you're visiting while your babies are sleeping, remember that your presence still matters. Talking softly, reading a story, or providing skin-to-skin care when appropriate are wonderful ways to bond.

When Should You Be Concerned?

Most sleepy premature babies are simply doing what their bodies need to do.

However, you should contact your baby's healthcare provider if your baby:

• Is difficult to wake for feedings

• Suddenly becomes much sleepier than usual

• Refuses multiple feedings

• Has trouble breathing

• Appears unusually floppy or difficult to arouse

• Has fewer wet diapers than expected

• Shows signs of illness, such as fever or poor feeding

Trust your instincts. If something doesn't seem right, it's always appropriate to call your healthcare provider.

My RN & Twin Mom Perspective

As both a registered nurse and a twin mom, I know it's easy to worry when your babies seem to spend most of their day asleep. We naturally want to see them awake, looking around, and interacting with us.

The truth is that sleep is one of the healthiest things a premature baby can do. During those long naps, their brains are developing, their bodies are growing, and they're conserving the energy they need for feeding and healing.

As they mature, you'll gradually see those quiet stretches give way to more alert moments. Every baby develops at their own pace, so try not to compare your twins to each other or to other babies.

🗣️ SLP Perspective from Dr. Judy

From a speech-language pathologist's perspective, sleep and feeding are closely connected.

Premature babies need enough energy to coordinate sucking, swallowing, and breathing safely. As their brains and nervous systems mature, you'll often notice they begin waking more consistently for feedings and showing stronger feeding readiness cues.

If you're unsure whether your baby is ready for more oral feeding, ask your healthcare provider about your baby's feeding milestones and readiness signs. Every premature baby develops these skills on their own timeline.

Frequently Asked Questions

How many hours do premature babies sleep?

Premature babies often sleep for much of the day, but the amount varies based on gestational age, medical condition, and feeding needs.

Is it okay to let my premature baby sleep?

Yes. Sleep is an important part of growth and development. However, continue following your healthcare provider's instructions about waking your baby for scheduled feedings if recommended.

Why does one twin sleep more than the other?

Even twins develop differently. It's common for one twin to sleep longer or wake more often than the other.

Should I wake my premature baby to play?

Most premature babies benefit more from restful sleep than extended periods of stimulation. Follow your healthcare provider's guidance about feeding schedules and enjoy short periods of interaction when your baby is naturally awake.

When should I call the doctor?

Contact your healthcare provider if your baby is unusually difficult to wake, refuses feedings, has trouble breathing, or if you notice any sudden change in their normal behavior.

Related Guides

• Preparing for Twins: What to Expect if They're Born Early

• Questions to Ask Your NICU Team

• Corrected Age vs. Actual Age: Understanding Your Twins' Development

• Bringing Twins Home from the NICU

• Twin Feeding Milestones: What to Expect During the First Year

References

• American Academy of Pediatrics. HealthyChildren.org.

• March of Dimes. Premature Babies.

• National Institute of Child Health and Human Development.

• MedlinePlus. Premature Infant.

Medical Disclaimer

This article is for educational and informational purposes only and should not replace medical advice. Every premature baby develops differently. Always follow your pediatrician's or healthcare provider's recommendations regarding your babies' sleep, feeding schedule, growth, and overall health.