What Is a Premature Baby?

Reviewed by Amita Shroff, MD on October 03, 2022

What Is a Premature Baby?

If your baby is a preemie, you'll have plenty of questions about how to give them the extra care they need. A lot depends on how many weeks before the due date your baby is born. The earlier the birth, the more complications the baby is likely to have.

Doctors call a baby "premature" if it's born more than 3 weeks before the due date. Since preemies haven't had as long to develop inside the womb, some may have health problems and need to stay in the hospital longer than babies born on time.

Most preemies are what's called late preterm, meaning they're born in weeks 34-36 of pregnancy. Your baby might also be:

  • Moderately preterm, born from 32 to 34 weeks
  • Very preterm, are born at less than 32 weeks
  • Extremely preterm, born at or before 25 weeks


Premature Baby Symptoms

At first, your baby may look different from other newborns you've seen:

  • Premature babies are smaller than those born closer to their due date, with less fat.
  • Your baby's head might look a little large for their body.
  • Their skin might seem thin, and it could be covered in a fine hair called lanugo.
  • Their features may look less rounded than those of full-term babies.

You may notice some other differences, too:

  • Your preemie may cry softly or not at all, at first, since their breathing system isn't fully developed. They may also have breathing problems.
  • They may have trouble feeding because they don't have reflexes for sucking and swallowing.
  • Your baby's temperature might be low, since they don't have much body fat to keep them warm.

As the baby grows and gains weight, they'll start to look and act more like other infants.

Premature Birth Causes and Risk Factors

Doctors don't always know why a baby is born prematurely. But you may be more likely to have a premature baby if you:


Premature Birth Prevention

There's no foolproof way to prevent a preterm delivery. But if you're planning a pregnancy, take these steps to stay healthy:

  • Wait at least 18 months between pregnancies.
  • Maintain a healthy weight.
  • Don’t smoke, drink, or use drugs.
  • Start seeing a doctor for prenatal care as soon as you think you're pregnant.
  • Get treatment for any health conditions you have.
  • Get any vaccines you need, and take care to avoid infections.
  • Try to reduce your stress levels.
  • If you have depression, get treatment for it.

If you're pregnant and at high risk of preterm labor, your doctor may give you:

  • Progesterone supplements. This hormone may help if you have cervical problems or a history of premature births.
  • An operation called cervical cerclage. If you have a "short" cervix, your doctor can stitch it closed to help support your uterus. They'll remove the stitches when you're ready to give birth.


What to Expect

Premature babies get extra care as soon as they're born. Your baby may need to see a neonatologist, a pediatrician who treats preemies.

Your doctor may suggest your baby get special care in a neonatal intensive care unit (NICU). Your baby may get hooked up to different machines. Each piece of equipment plays an important role in getting them well and ready to go home.

For example, nurses may place your baby in an incubator, a plastic bassinet that keeps them warm. They may put sensors on their body to keep tabs on their heart rate, blood pressure, and temperature.

Your preemie may also need a machine called a ventilator to help them breathe. They could get fluids and nutrients through an IV. Nurses may put a feeding tube into your baby's nose to feed them breast milk or formula.

Even though your little one is in the NICU, you'll still get your chance to bond. Once your doctor gives the OK, you'll be able to touch, hold, and breastfeed or bottle-feed your baby. You may be encouraged to pump breast milk until your baby learns to nurse to help them grow and fight infection.  

Many NICUs have moms and dads give skin-to-skin care for preemies. You may hear them call it kangaroo care. You place your infant against your bare chest, which helps them stay warm, breathe easier, and sleep more deeply. Some babies nap on their parents' skin. Others simply enjoy the close contact.

Not all premature babies have complications. And for those who do, today's advanced medical care means babies born very early are more likely to survive -- and thrive -- than ever before.

Premature Baby Complications

Premature babies are at risk of complications because their organs didn't have as much time to develop in the womb. When babies are born very prematurely, they are at higher risk for some health problems.

Some short-term issues that can happen are:

Loss of body heat. Lack of body fat makes preemies likely to lose body heat quickly. If their temperature gets too low, they can have breathing problems and low blood sugar.

Breathing problems. Some preemies have apnea, long pauses in their breathing. Another condition, called respiratory distress syndrome. happens when your baby's lungs don't make enough of a liquid called surfactant. If this happens, doctors will treat the baby with an artificial version of the liquid, which helps the lungs expand. They may need to put the baby on a ventilator.

With bronchopulmonary dysplasia, your baby will need oxygen for several weeks or months. Preemies often outgrow this as their lungs mature.

Heart problems. Patent ductus arteriosus is when your baby has an opening between two major blood vessels leading from their heart. It often closes on its own. Preemies also may have low blood pressure. That could mean they need IV fluids, medicines, or maybe a blood transfusion.

Brain problems. Very early birth makes a baby more likely to have bleeding in the brain, called intraventricular hemorrhage. These often go away without doing much harm.

Digestive problems. After they start feeding, some preemies can get a condition called necrotizing enterocolitis. It happens when tissues in their intestines get inflamed. The risk is lower in babies who are only breastfed.

Blood problems.Anemia, in which your baby's body doesn't make enough red blood cells, can keep your baby from gaining weight and being active. Doctors treat it with iron supplements, medicine, or blood transfusions.

When your baby has jaundice, their skin turns a yellowish color. It happens because a chemical called bilirubin builds up in their blood. Your baby may need treatment with special lights.

Possible long-term complications include:

Vision problems.Retinopathy of prematurity happens when the baby's retina -- a layer of nerve cells at the back of the eye that senses light -- isn't fully developed. It can lead to scars on the retina. In rare cases, the retina can get detached.

Hearing problems. Preemies are at increased risk for hearing loss. They are usually tested in the neonatal nursery. Your pediatrician can follow up with care.

Dental problems. Preemies may teethe late, or have teeth that are discolored or not aligned properly.

Cerebral palsy. This is a disability that affects movement and muscle tone. While most people who have it were not born prematurely, premature birth is a risk factor. Occupational and physical therapy can help babies and kids who have cerebral palsy.

Learning and behavior problems. Premature babies are often slower to hit development milestones than full-term infants. They may have learning disabilities and behavior issues later on. Talk to your doctor if you're concerned.

Other health problems. Preemies are more likely to end up with long-lasting conditions like infections, asthma, and problems with feeding.

Going Home

How long until your baby goes home varies. It could be a few days or weeks after birth.

Your baby's doctor will clear them to head home once your baby:

  • Breathes on their own
  • Can breastfeed or bottle-feed
  • Weighs at least 4 pounds
  • Gains weight steadily
  • Stays warm without help

Your baby might need special equipment even once they're settled in at home. Some babies use monitors, like those for sleep apnea, or continue to get oxygen. No matter what your baby needs, your nurses and doctors will teach you how to use the equipment before you leave. They should train you in infant CPR, too. And remember to get your baby any vaccines that the doctor recommends before leaving the hospital.

Taking care of your preemie will likely take up much of your time and attention, but don't forget to take care of yourself, too. Get rest, eat healthy food, and accept help from friends and family.

It's normal to feel like you're on an emotional roller coaster. Think about joining a support group where you can talk to other parents who are going through the same things you are. You can also meet with a counselor to discuss the challenges you face.

Show Sources


March of Dimes: "Premature Babies," "Preterm Labor and Premature Birth: Are You at Risk?" “Common conditions treated in the NICU.”

National Institutes of Health: "Premature Babies."

American Academy of Pediatrics: "Preemie," “How you can participate in the care of your baby in the NICU,” “What is a neonatologist?”

Mayo Clinic: "Premature birth."

National Heart, Lung, and Blood Institute: "What Is Respiratory Distress Syndrome?"

MyHealth Alberta: "Learning About Anemia of Prematurity."

Christine Gleason, MD, neonatologist, Seattle Children's Hospital; professor of pediatrics, University of Washington; neonatal consultant, March of Dimes.

Association of Women's Health, Obstetric and Neonatal Nurses: “Premature expectations.”

Kids Health: “When your baby's in the NICU.”

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