Mother holding a newborn baby's forehead.

If your baby is born prematurely (prior to 37 weeks gestation), there are a few key differences you should expect compared to a full-term newborn. Eleven to 13 percent of all pregnancies result in premature birth, and are often categorized in the following ways:

  • Late preterm: born between 34 and 36 weeks
  • Moderately preterm: born between 32 and 34 weeks
  • Very preterm: born at less than 32 weeks 

Knowing what to anticipate can be really helpful if your baby makes an early appearance in the world, mama. Here are five major differences you can expect between a premature baby and a full-term baby. 

Weight (and Size) Differences

The average full term baby’s birthweight is around 7 pounds. The weight of a premature infant varies greatly and depends on the baby’s gestational age at birth. A premature baby can weigh anywhere from one pound to 5 pounds. It can be a bit overwhelming to see such a tiny baby, especially for the first time. Rest assured they are pint size babies with 10 fingers and 10 toes.  Premature babies have special needs due to their small size that require specialized care in the NICU. These tiny babies will continue to grow outside of mommy until they are big enough to go home from the NICU.  


A premature newborn won’t look like the chubby newborns you see in commercials. The earlier your baby is born, the smaller they’ll be with sharper features, and their head will appear larger in comparison to their bodies. Preemies also have very little body fat which will make their skin seem thinner and more transparent. This is normal. 

You might also notice that your little one is a bit furry. This hair, called lanugo, typically falls off in the womb in the last few weeks of pregnancy, but preterm babies often don’t have a chance to shed it before birth. Not to worry, it will eventually come off on its own.

There also might be differences in the amount of vernix (the white, waxy-looking substance that protects baby’s skin) on a premature baby just after birth. Very preterm babies might not have much at all (since it’s created later in the pregnancy), where moderate or late-preterm babies might have more vernix than a full-term baby, since it hasn’t had the chance to shed yet in the uterus.


A premature infant’s lungs and respiratory system simply aren’t developed enough to function like a full-term baby’s would. It might be surprising to know that some premature babies might not even cry (or may cry very softly) since their lungs aren’t quite strong enough to produce loud sounds. If your premature baby needs help breathing, they may receive extra oxygen or even be placed on a ventilator or CPAP breathing assistance to ensure all of the organs in the body are getting enough oxygen. As your little one’s organs continue to develop and strengthen, they will be able to be removed from breathing assistance or oxygen once their provider feels they’ve hit the correct milestones.


Depending on a premature baby’s maturity and needs, they might also need specialized ways of feeding. If they don’t have the skills to breast or bottle-feed quite yet, some preemies might require nutrition intravenously or through a feeding tube, placed through their nose or mouth that goes directly to the stomach. But that doesn’t mean that you can’t help feed your baby, mama. Breast milk is ideal for premature babies, as it can provide antibodies that will help fight infections and benefit their immune response. If your premature baby is too little to nurse at the breast, you can pump breastmilk for tube or bottle feeding Your baby’s provider will help determine the best method for you and your little one.

Adjusted Age and Milestones

In order to understand where your premature baby should be in terms of hitting developmental milestones as they get older, you’ll need to know how to calculate their adjusted age. This adjusted age will give you a better sense of what’s ‘normal’ for their developmental markers (such as sitting up on their own, rolling over, etc.) until they’re 2 years old. To calculate your baby’s adjusted age, take their actual age (in weeks), and subtract the number of weeks they were born early. For instance, a 10-week-old baby born four weeks early has an adjusted (or corrected) age of 6 weeks old.

Whether your baby is born prematurely or not, their provider will keep a close eye on your little one’s development to ensure they’re progressing as they should. Keep in mind, mama—you know your baby best. You’ll know the areas your baby is conquering without a problem, and you’ll also have an idea if they need help in others. Chat with your baby’s provider about early intervention (EI) services to support and encourage their development (such as physical therapy, speech therapy, feeding therapy, etc.).