Outcomes of extremely preterm birth

Scientific advances have led to more extremely preterm infants surviving delivery. What are the outcomes for these infants?

With science leading to better outcomes for preterm infants, even in those who were born extremely preterm, it’s become increasingly important to understand how extreme prematurity impacts mortality, in-hospital morbidity, and 2-year neurodevelopmental outcomes. An investigation of extremely preterm infants born between 2013 and 2018 provides some much-needed data.1

Investigators ran an observational study that used a prospective registry of infants born at 22-28 weeks’ gestational age in 19 US academic medical centers. They looked at survival as well as 12 different in-hospital morbidities, which including necrotizing enterocolitis, infection, intracranial hemorrhage, retinopathy of prematurity, and bronchopulmonary dysplasia. At 22-26 months’ corrected age the infants were given an assessment for health and functional outcomes, including neurodevelopment, cerebral palsy, vision, hearing, rehospitalizations, and need for assistive devices.

A total of 10,877 infants were included, 49.0% female and 51.0% male. In this cohort, 78.3% survived to be discharged from the hospital, which was an increase from the 76.0% (adjusted difference, 2.0%; 95% CI, 1.0%-2.9%) seen in 2008-2012. Survival to discharge was 10.9% for infants at 22 weeks and 94.0% for infants at 28 weeks. Among actively treated infants, survival was 30.0% among those born at 22 weeks and 55.8% at 23 weeks. The investigators found that all in-hospital morbidities were more likely to occur in infants who born at an earlier gestation age. The percentages of in-hospital morbidities were 8.9% (890/9956) of infants had necrotizing enterocolitis; 2.4% (238/9957) had early-onset infection; 19.9% (1911/9610) had late-onset infection; 14.3% (1386/9705) had severe intracranial hemorrhage; 12.8% (1099/8585) had severe retinopathy of prematurity; and 8.0% (666/8305) had severe bronchopulmonary dysplasia. A total of 2566 infants were seen for follow-up. By the time of a 2-year follow-up, 8.4% (214/2555) of children had moderate to severe cerebral palsy; 1.5% (38/2555) had bilateral blindness; 2.5% (64/2527) required hearing aids or cochlear implants; 49.9% (1277/2561) had been rehospitalized; and 15.4% (393/2560) required mobility aids or other supportive devices. In the group of 2458 fully evaluated infants, the investigators determined 48.7% had no or mild neurodevelopmental impairment at follow-up; 29.3% had moderate neurodevelopmental impairment; and 21.2% had severe neurodevelopmental impairment.

The investigators concluded that for 2013-2018 the survival to discharge in extremely preterm infants had improved from the levels seem in 2008-2012. However, they also noted that among infants who were born at less than 27 weeks’ gestational age both neurodevelopmental impairment and rehospitalization were common when they were aged 2 years.


  1. Bell E, Hintz S, Hansen N, et al. Mortality, In-hospital morbidity, care practices, and 2-year outcomes for extremely preterm infants in the US, 2013-2018. JAMA. 2022;327(3):248-263. doi:10.1001/jama.2021.23580

This article was originally published on Contemporary Pediatrics®.