5 Facts About Premature Babies

Father taking care of his premature baby doing skin to skin at hospital
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Whether you or a loved one has welcomed a premature baby, or you are just curious about how preterm birth can affect a little one, learn more about prematurity and its effects. Some of these facts may come as a surprise.

A Late Preterm Baby Is Still a Preemie

Don't let the term "late" fool you! There is nothing late about these babies. A late preterm infant is a baby born three to six weeks early, or between 34 and 37 weeks of gestation. In the last six weeks of pregnancy, babies usually gain about a half a pound per week, so babies born a few weeks early are smaller than full-term newborns—but they are not just smaller infants.

Late preterm babies have their own health considerations that can be pretty serious, including respiratory problems, low blood sugar levels, feeding difficulties, and trouble maintaining their body temperature. Babies born even just a few weeks preterm often have low calcium and phosphorus stores, because they miss out on the important last weeks of pregnancy when two-thirds of bone mineralization takes place.

Late preterm babies also have an increased risk of infection due to an immature immune system. Antibodies from the pregnant parent are passed to the unborn baby through the placenta during the final stage of pregnancy, though emerging research shows that premature infants born as early as 24 weeks still receive these parental antibodies. Other aspects of the neonatal immune system, such as underdeveloped lungs or a weak skin barrier, are considered possible causes for a preemie's susceptibility to infection.

Late preterm babies also have an immature neurological system. The brain of a baby born at 35 weeks gestation weighs only two-thirds of that of a full-term baby.

An infant’s nervous system is still developing during those final months and weeks in the womb. It is during this time that a fatty substance called myelin develops; this speeds up the transmission of nerve impulses and forms a sheath around the nerve fibers. Because of their immature neurological system, premature babies often find it hard to calm and comfort themselves and may need extra time and careful attention as they grow and learn in their new environment outside the womb.

Hiccups Are Common (and Normal!)

"Your baby has hiccups; they must be growing!" This common assumption comes from an old wives' tale and isn't quite accurate when it comes to premature babies. 

Inside the womb, you may have noticed that your baby had the hiccups quite a bit, but this typically doesn't start until the second or third trimester of pregnancy. Hiccuping in the womb is in response to the baby swallowing amniotic fluid while "practice breathing" in preparation for life after birth.

During the second trimester of pregnancy, a baby begins swallowing and releasing some of the surrounding amniotic fluid in the womb. During the third trimester, at around 34 weeks, amniotic fluid levels are at their highest. Amniotic fluid has an array of growth factors, anti-inflammatory, and anti-infective components that help to mature the baby's gut microbiome, building immunity and preparing it for the introduction of milk after birth.

After birth, a newborn born at term may continue to hiccup quite frequently, and it may very well be tied to feeding. Hiccups are caused by sudden contractions of the diaphragm triggered by irritation of the muscle and stimulation of the vagus nerve—the nerve that connects the brain to the abdomen. Hiccups are fairly common in newborn babies and are only cause for concern if they persist beyond the first 12 months of life.

For a premature baby, the hiccup is more of a physiologic response rather than a physical cause. The premature baby’s neurological system is immature and will respond to stress differently because of it. The brain regulates bodily functions such as heart rate, breathing rate, blood pressure, and temperature.

A premature baby has premature organs regulated by an immature nervous system, which can cause physiological stress responses to occur if the baby becomes overstimulated or disorganized in their behavior. Some of these behavioral stress cues are sneezing, spitting up, gagging, and hiccupping. It’s important to learn your baby’s stress and stable cues so that you can respond to and comfort your baby in the very best way possible, as they grow and develop in the foreign NICU world.

Human Milk Is Ideal for Preemies

With research, medical, and scientific advancements, we have come a long way in the world of preemie care. However, no matter how advanced it gets, the neonatal intensive care unit (NICU) can only try to replicate what nature does best inside the womb to support the growth and development of the baby.

This is also true when it comes to the nutritional needs of the newborn. Formula companies have been able to create milk that is specific for premature babies' growth and nutrition needs. However, research shows that nature still provides the most ideal nutrition, especially when it comes to the special needs of a premature infant's immature immune and gastrointestinal systems.

Human milk has as many as 130 oligosaccharides, prebiotics that are specific to human milk and essential for preterm infant growth. These good bacteria help colonize the premature baby’s gut with friendly, healthy live cells and antibodies. These antibodies help to protect against severe intestinal inflammation and an infection called necrotizing enterocolitis (NEC), which can be devastating for a premature baby.

Colostrum contains anti-inflammatory and anti-infective components similar to that of amniotic fluid. Human milk feedings, and specifically colostrum feedings, especially in the early days, stimulate rapid growth of the intestinal tract and mucosal lining which helps mature and protect it just like amniotic fluid does while the baby is in utero. Human milk builds immunity and protects the premature baby from infection and disease.

Human milk has so many powerful benefits that help a preterm baby not only grow and survive but thrive in the NICU. Human milk helps reduce other serious preterm complications and should be considered an essential part of neonatal care. Myriad evidence points to why it can be a life-saving medication for fragile infants.

NICU Graduation Is About More Than Weight

When your premature baby hits 5 pounds, it is a major milestone worth celebrating. But it may not necessarily mean that your baby is ready to be discharged from the NICU.

Discharge from the neonatal intensive care unit is based on milestones, and a premature baby must typically meet the following criteria before they are ready to go home:

  • Able to hold their temperature (within normal range) on their own in an open crib without the aid of a hat or additional blankets
  • Able to take all of their milk by mouth—breastfeeding or bottle feeding—with ease while also getting sufficient calories
  • Gaining adequate weight
  • Breathing on their own. Most babies are off oxygen when discharged from the NICU, but some infants may need supplemental oxygen for a longer period of time and may be sent home with this therapy.
  • Free of episodes of apnea (pauses in breathing) and bradycardia (slow heart rate) or change in color. You may be able to take your baby home on a monitor if they have short, self-resolving episodes that do not require any intervention.

Before discharge, your baby may also need a car seat study or test, a hearing screen, or important specialty appointments scheduled. You may also need some education on CPR, safe sleep, and infant care. Start planning early so that when your baby is ready to go home, you are too!

Since every baby is different, and their journeys will vary from just a few days to many months, it's difficult to say when your baby will hit all their milestones and be ready for discharge. Keep track of your baby’s progress by starting a journal or checklist, and celebrating these milestones as they happen.

Preemie Milestones Can Be Unpredictable

Don’t compare your baby to your friend’s baby who was born the same week or your neighbor’s nephew who was walking at nine months of age. It’s easy to get caught up in these comparisons, but it's just not worth the stress it may cause. Keep in mind that your baby is still a preemie when they're discharged from the hospital, and just because you have left the NICU does not mean your baby is now considered a full-term baby.

Your baby is a premature baby who has now hit full-term gestation. There is a big difference, especially if your baby has had a rough start. Your premature baby is now healthy and stable enough to continue to grow outside of the hospital. That is a pretty amazing feat, so try to remember to refer to your actual due date rather than your baby’s birth date when following a developmental milestone guideline.

For example, a baby that was born at full term will begin to show signs of early communication at 2 months of age when they discover their voice and begin to make cooing sounds. This is an exciting milestones achievement! However, a premature baby born two months early may have only just mastered the suck-swallow-breathe milestone at 2 months old and can now take all of their milk by mouth. This is exciting too but is more on track developmentally with that of a full-term newborn.

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