Premature Birth and Survival Statistics

At What Point in Pregnancy Can a Baby Survive Premature Birth?

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Many women, especially those who are anxious after a past pregnancy loss, breathe a sigh of relief after the pregnancy reaches the point at which the baby would be able to survive if born early. What point, though, is that really? The answer is somewhat complicated.

Premature Birth Survival

Strictly speaking, most doctors define the age of viability as being about 24 weeks of gestation. In many hospitals, 24 weeks is the cutoff point for when doctors will use intensive medical intervention to attempt to save the life of a baby born prematurely.

A baby born at 24 weeks would generally require a lot of intervention, potentially including mechanical ventilation and other invasive treatments followed by a lengthy stay in a neonatal intensive care unit (NICU).

In the hands of experienced specialists, though, babies born slightly earlier may have a chance at survival. Babies born at 23 weeks may survive with these specialists in a state-of-the-art NICU, but the odds of survival are much lower. The earliest baby to have ever survived premature birth was born at 21 weeks and 6 days, and this was reported in the news as having been a "miracle."

Odds of survival increase as the pregnancy progresses, and even an extra week in the womb can make a difference. In general, premature babies born closer to 37 weeks will be better off than those born before 28 weeks.

Factors that Affect Premature Babies' Survival

But the matter is not always as simple as being past a particular point in the pregnancy at the time of the birth.

Multiple factors can play into whether or not a baby will survive premature birth, for example, the baby's birth weight. Low birth weight is independently linked to reduced odds of survival and a higher risk of disabilities and health problems.

In addition, if the early birth resulted from induction or C-section due to a medical condition, such as placental abruption, the effects of that condition can affect the baby's health and survival also — such as if there was oxygen deprivation before the delivery.

Another factor can be if doctors had time before the birth to treat the baby with steroids to speed up lung development. The patient/mother gets the steroids, which then pass through the placenta to the fetus. A very premature baby treated with steroids before birth is more likely to survive than a baby born unexpectedly premature, because the steroids can make a difference in whether or not the baby is able to breathe outside the womb.

Girls may also be more likely to survive very early premature birth, as are babies born in singleton vs. multiple pregnancies.

Odds of a Premature Baby's Survival by Length of Pregnancy

Length of PregnancyLikelihood of Survival
23 weeks17%
24 weeks39%
25 weeks50%
26 weeks80%
27 weeks90%
28-31 weeks90-95%
32-33 weeks95%
34+ weeksAlmost as likely as a full-term baby
Sources: March of Dimes, Quint Boenker Preemie Survival Foundation

In addition to the risk of death, babies born very prematurely can face high odds of having some level of learning disabilities or other developmental impairment, but the intensity of the disabilities or impairment can vary heavily. This can depend on many factors, including the need for and types of treatment received in the immediate neonatal period. The more intense treatment, sometimes the more intense the risk factors for these extremely small and fragile babies.

In essence, the very procedures that are life saving, also have the ability to limit their abilities as they live that life. The problem is, it is nearly impossible to tell which babies will have problems and how severe these problems will be later in life.

For every twenty-six week baby, about twenty percent of them will have no long-term problems. That leaves about eighty percent with some form of developmental or physical problem in their lives. Though it is important to note again that these can very in severity.

About thirty-four percent of babies born at the twenty-six week mark will have a mild disability. A mild disability is defined as something like near-sightedness or minor cognitive impairment. So even within this category, you can see that there is still a wide range of potential problems.

Twenty-four percent of babies born at the twenty-six week mark will have a moderate disability.

A moderate disability includes problems such as visual/hearing impairment or cerebral palsy with the ability to walk. Cerebral palsy in and of itself can drastically vary from person to person. Early intervention can also help with preventing or lessening some of the symptoms.

The remaining twenty-two percent will have severe disabilities.

This can include blindness or profound deafness. It can also include cerebral palsy with no ability to walk. This is typically what people think of when they think of developmental disabilities following a preterm birth.

Babies who are born early face the risk of learning disabilities and other problems, but the specific odds of these problems vary heavily on factors, such as birth weight and whether or not there was oxygen deprivation before birth. This is true, even for babies who you would not necessarily categorize as preterm, including those born in the early term. The baby’s brain undergoes much growth and development in the last weeks of pregnancy.

As you can see, there is much more to discuss when it comes to preterm birth. It is not merely a discussion of will the baby survive the birth, but what are the long-term outcomes for this baby. There is a wide range of possibilities that are very specific to the situation at hand. Questions to consider asking include:

  • What is the gestational age at which my baby was (or will be) born?
  • Was their oxygen deprivation prior to birth? What are the expected consequences of that? What tests were run to check the severity? What tests will be done and when to look at the potential outcomes?
  • What types of interventions have been used or will be used in my baby’s care? What are the risks and benefits of each of these treatments? What are the alternatives?
  • What problems should I watch for after discharge? In the first year? When my child starts school?
  • What type of follow up will my baby need? Is there an early intervention program?

Sources:

Elsworth, Catherine, "Youngest Premature Baby's Survival Called a 'Miracle'." The Daily Telegraph 21 Feb 2007. Accessed 28 Jun 2015.

March of Dimes, "Fact Sheet: Preterm Birth." Quick Reference: Fact Sheets October 2013. Accessed 27 Jun 2015.

Tyson, Jon E., Nehal A. Parikh, John Langer, Charles Green, and Rosemary D. Higgins, "Intensive Care for Extreme Prematurity — Moving beyond Gestational Age." New England Journal of Medicine 17 Apr 2008. Accessed 29 Jun 2015.

Quint Boenker Preemie Survival Foundation, "Premature Birth Statistics." Accessed 29 Jun 2015.

Edited by Robin Elise Weiss, LCCE

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