There has been a significant increase in survival without major neonatal morbidity for infants born at 25-28 weeks’ gestation in the United States in the past 2 decades, researchers reported online Sept. 8 in JAMA.
Survival without major complications improved by about 2% per year for these babies, said Dr. Barbara Stoll of Emory University in Atlanta and her associates. But outcomes for earlier preterm births were mixed. “Although overall survival increased for infants aged 23 and 24 weeks, few infants younger than 25 weeks’ gestational age survived without major neonatal morbidity, underscoring the continued need for interventions to improve outcomes for the most immature infants,” the investigators said.
Despite advances in perinatal care, preterm infants face disproportionate rates of morbidity and mortality. The investigators studied outcomes for 34,636 such babies who were born between 1993 and 2012 at 26 U.S. Neonatal Research Network centers, including 8 that participated for the entire study. All the infants were born at 22-28 weeks’ gestation and weighed 401-1,500 g at birth (JAMA 2015;314[10]:1039-51).
“The percent of infants from a multiple birth increased from 18% in 1993 to 27% in 1998 (P less than .001),with no further increase noted,” Dr. Stoll and her associates reported.
Between 2009 and 2012, survival improved the most for infants born at 23 weeks’ gestation (from 27% to 33%) and at 24 weeks’ gestation (from 63% to 65%). But survival increased only slightly for infants born at 25 and 27 weeks’ gestation, and remained static for infants born at 22, 26, and 28 weeks. Furthermore, although survival without major morbidity improved markedly for infants born at 25-28 weeks, it did not change for those born at 24 weeks.
Rates of late-onset sepsis fell among all gestational age groups, but bronchopulmonary dysplasia rose significantly (P less than .001). The latter “may partly be explained by increased active resuscitation, intensive care, and increased survival, especially for the most immature infants,” the investigators said. Use of prenatal corticosteroids rose from 24% to 87% during the study period (P less than .001), as did rates of cesarean delivery (from 44% to 64%; P less than .001), they added.
The preterm registry used in the study was supported by the National Institutes of Health, National Institute of Child Health and Human Development, National Center for Research Resources, and National Center for Advancing Translational Sciences. The investigators reported no financial disclosures.