So, your little one couldn’t wait to join you in the big, big world and has decided to make a grand entrance! If your baby is premature, or “preterm,” they’re in good company — about 1 in 10 babies are born prematurely in the United States.

A premature birth is one that happens at least three weeks before your estimated 40-week due date — so, before the 37th week of pregnancy. That said, “premature” is a range.

Premature birth ranges are called:

  • extremely preterm (before 28 weeks)
  • very preterm (28 to 32 weeks)
  • moderate preterm (32 to 34 weeks)
  • late preterm (34 to 37 weeks)

You may also hear the term “periviable birth,” which refers to delivery between 20 and 26 weeks, according to the American College of Obstetricians and Gynecologists.

How early your baby is born makes a difference in what kind of interventions they might need. The more premature a little one is, the higher the chance of some complications. Each gestational week makes a difference in survival rate, when it comes to premature babies.

Doctor’s don’t always know why a baby is born premature, and they can’t always prevent it. What’s more, the research on preemie survival rates is extremely broad.

Outcomes vary widely based on country, maternal factors, and baby’s birth weight. But rest assured, the survival rate for babies born extremely preterm without neurodevelopmental problems has been improving since 2000.

A baby born between 20 and 26 weeks is a considered to be periviable, or born during the window when a fetus has a chance of surviving outside the womb. These babies are called “micro-preemies.”

A baby born before 24 weeks has less than a 50 percent chance at survival, say the experts at University of Utah Health.

However, according to this 2016 analysis of more than 8,300 deliveries in the United States, babies born at 24 weeks had a 68 percent chance of survival. A 2016 cohort study of more than 6,000 births found a survival rate of 60 percent. (Utah Health notes a 60 to 70 percent survival rate for this gestational age.)

With an extremely premature birth, you and your baby may face some rough times (and choices) together. Fortunately, advances in medicine means even the tiniest babies can likely get bigger and stronger in neonatal intensive care units (NICU).

About 40 percent of babies born at 24 weeks will have health problems, says the Irish Neonatal Health Alliance. Some of these complications may happen right away, or others that appear later in life.

Risks for a baby born this early include complications regarding:

Skin and warmth

Your tiny one will need to go into an incubator (like a portable womb) right away to keep them warm. Babies born this early have not yet had the chance to develop brown fat — the kind just under the skin that keeps them toasty. Their skin will also be extremely thin and delicate.


A baby’s lower lungs and airways are only just beginning to develop around 24 weeks. A baby born at this time will need help to breathe. This might mean little tubes going into their nose, as they grow in the incubator.


At about 24 weeks in the womb, a baby’s eyes are still closed. Their eyelids and eyes are not yet developed enough to open them. Your baby will need to have soft cotton or gauze taped over their eyes to protect them from the light as their sight continues to develop.

In some cases, a baby’s eyes might not grow as they should, which could lead to vision problems or even blindness.


Amazingly, an extremely premature baby already has fully formed ears. Your baby can start to hear you at about 18 weeks gestation! However, your little one’s eardrums are still very delicate and sensitive at 24 weeks. Some babies born this early may have problems hearing or experience deafness.

Other issues

Some extremely premature babies may have issues that affect the brain and nervous system as they get older. Some of these are serious. Complications include cerebral palsy, learning problems, and behavioral issues.

If your baby is born at 26 weeks, they’re still considered “extremely preterm.” But a lot can improve for a developing baby in just a couple of weeks of gestation time, increasing chances of survival.

Babies born at 26 weeks were found to have a survival rate of 89 percent in the 2016 analysis and 86 percent in the 2016 cohort study.

A big difference contributing to the jump in survival rate at 26 weeks versus 24 weeks is your baby’s lung development. By about 26 weeks of gestational age, a baby’s lower lungs have grown and developed little air sacs called alveoli.

Your baby will still be too little to breathe on their own, but their lungs will be more developed and stronger. Your little one will still need to be in an incubator for warmth with breathing tubes to help bathe them in life-giving oxygen.

About 20 percent of babies born at 26 weeks may still have some health problems as they age. These might include issues with:

Babies born at 26 weeks may also develop heart problems.

A baby born after 28 weeks is considered “very preterm” but has a big head start compared to babies born just 2 to 4 weeks earlier. This is because their vital organs — like the heart and lungs — are much more developed.

According to the University of Utah Health, the survival rate for your baby is 80 to 90 percent at 28 weeks. Some clinical studies have even more promising data, showing survival rates of 94 percent and 98 percent at this age.

Only 10 percent of babies born at 28 weeks risk long-term complications. These can include:

What a difference a few womb weeks make! Babies born between 30 and 32 weeks, while still considered preterm, have at least a 99 percent chance of survival. They also have very low risk of health and development complications later on.

If your baby is born at 34 to 36 weeks they are in a new category called “late preterm.” This is the most common kind of premature baby. It’s also the one with the least risks because your baby has more time to grow and develop inside you.

In fact — good news — a preemie baby born at 34 to 36 weeks has nearly a 100 percent chance at survival and the same chances at long-term health as a baby who was born full-term.

Still, your 34- to 36-week-old baby might be smaller and a bit more delicate than a 40-week or full-term baby. Your doctor may recommend that they stay in an incubator at the hospital for a week or two, so they can rest and get a bit bigger before going home.

If your baby is born prematurely, there are several things that affect their survival rate and how healthy they’ll be as they age. A week or two more in the womb can make a big difference for your baby.

Medical advances in caring for premature babies means better outcomes, and more peace of mind for parents. While every week in the womb will give you more assurance, know that chances for your preemie’s survival are increasing every year.