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The Premature Baby Development Process

The Premature Baby Development Process

Here’s what you can expect when it comes to your premature baby’s development.

Medically reviewed by a board-certified pediatrician

Nervous System | Size & Weight | Skin & Genitals | Face & Body Hair | Bones | Muscles & Reflexes | Sleep | Sense

Even though your newborn may be in the NICU, they’re already developing their own adorable little personality. But since they arrived early, your baby has a bit more growing to do. Learn more about preemie development and what to expect for your little one.

Premature baby development: Nervous system

Your baby's nervous system controls how well their vital organs function. Since their nervous system is still developing, their heart rate, breathing, nerves, and muscles aren't working properly just yet. Here are some things you’ll notice as their nervous system gains control:

  • As their heartbeat becomes regular and breathing rate grows stronger, your infant won’t need medicines to help regulate this for them.
  • Lungs will develop until a respirator is no longer needed.
  • As the digestive system matures, your baby will progress from IV feedings to tube-feedings and eventually to breast or bottle.

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Premature baby development: Size and weight

Many premature babies weigh less than two pounds. During the last four weeks of pregnancy, a full-term baby gains about a pound each week. Premature babies miss out on this baby fat and because of this, a premature baby can look wrinkled with their fingers, toes, and nose appearing a bit long compared to the rest of their body. As their fat layer develops, this disappears, and they start to fill out.

During their first few days, your baby may actually lose a few ounces. This is normal. It happens with full-term babies, too. After that, they'll gain weight more steadily. Weight gain may fluctuate, losing an ounce or two some days. The rate at which your baby gains weight helps the NICU staff tell how quickly your infant is getting stronger.

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Premature baby development: Skin and genitals

A premature baby's skin is red and wrinkled and may appear almost transparent with tiny veins visible below the skin's surface. Premature babies of all ethnic groups have the same dusky-red skin color when they’re born. Their natural skin color develops over time.

Both premature boys and girls have immature genitals, which may look a bit unusual compared to those of a full-term baby. Your baby's sex organs may look larger than average. Don’t worry; they’ll look more proportional in a few weeks.

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Premature baby development: Facial features and body hair

Your baby's facial features are well developed, but their outer ears are still soft and limp. Their ears might lie flat against their head and not spring back when folded over. As your baby develops, their ears will look more like those of a full-term infant.

Your newborn may not have eyebrows or eyelashes just yet. They may, however, have a light covering of hair on their body, called “lanugo.” It may be heavy—especially around the shoulders—or just a light peach fuzz. Don’t fret—this hair usually disappears in a few days or weeks.

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Premature baby development: Bones

A premature baby's bones are very soft and easily molded, especially on their skull. Once they’re born, their nice rounded head begins to flatten from lying down. This is temporary. Your baby’s head will round out as they develop.

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Premature baby development: Muscle tone and reflexes

Your little one can stretch, yawn, and move their little arms and legs. But because your infant lacks muscle tone, they might be limp and flexible.

Some premature babies sleep with their feet tucked up next to their heads. While it looks uncomfortable, it may be a position they enjoyed in the womb. They may also stiffen suddenly and then go limp. This is common and is likely because their nervous system isn't fully developed.

Your baby’s fingers might be too weak to maintain a grip, or their arms and legs might flail about. As their nervous system develops, they'll gain better control of the muscles in their entire body. Movements will become smoother. Soon they’ll be able to make their muscles move.

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Premature baby development: Sleep patterns

Since premature babies require so much sleep, your baby might not be wide awake or pay attention to what's going on. Expect them to sleep as much as 15-22 hours a day at first. Being alert might be hard for them, but other responses are already like those of a full-term baby. As your baby grows, it’ll be easier to predict their sleep patterns.

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Premature baby development: Senses

Your baby can hear better than they can see, right now. But their sight will improve in time. If you talk to your baby, your little one will quickly get to know your voice.

Your infant can sneeze, hiccup, smile, and may even suck their thumb—skills acquired before birth that make for perfect photo and video moments.

Your baby recognizes types of touch and they’re calmed by your gentle touch, being held and rocked, or swaddled in a warm blanket. Many premature babies like to be covered or firmly wrapped in a blanket.

Even a very premature baby can taste the difference between something sweet and something salty. Like most children, they tend to prefer the sweet.

A full-term baby has a sense of smell so well developed that they recognize you by your scent alone. No one knows for sure what premature babies can smell, but some nurseries place an article of the mother's clothing in the baby's incubator in hopes that it will give a sense of your comforting presence.

It's going to take some time for your premature baby to grow and develop. The best thing you can do right now is take care of yourself and spend time with your baby, talking to them, touching them and giving them all the love.

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All information on Enfamil, including but not limited to information about health, medical conditions, and nutrition, is intended for your general knowledge and is not a substitute for a healthcare professional's medical identification, advice, or management for specific medical conditions. You should seek medical care and consult your doctor or pediatrician for any specific health or nutrition issues. Never disregard professional medical advice or delay seeking medical treatment, care, or help because of information you have read on Enfamil.