HealthDay News — Survival rates for extremely premature infants — those born only after 22 to 28 weeks of gestation — are increasing, results of a study published in the New England Journal of Medicine indicate.
“Understanding the causes and timing of death in extremely premature infants may guide research efforts and inform the counseling of families,” wrote Ravi Mangal Patel, MD, an assistant professor of pediatrics at the Emory University School of Medicine in Atlanta, and colleagues.
To determine the survival rate of premature infants in the U.S., the investigators analyzed data from 6,075 deaths among more than 22,248 live births with gestational ages of 22 to 28 weeks. The births occurred between 2000 and 2011. The infants were followed from birth for 120 days, or until they died, left the hospital, or were transferred to another hospital. Infants hospitalized for more than 120 days were evaluated until they died or until they aged one year.
The death rate for extremely premature infants dropped by nearly 10% during the study period, reported the scientists. Overall, 40.4% of the deaths happened with 12 hours after birth. Another 17.3% happened after 28 days. The largest declines in mortality were in those born at 23 or 24 weeks of gestation. The decrease in deaths from breathing complications made up 53% of the overall reduction in mortality.
Deaths from infections and nervous system problems also dropped, but deaths from necrotizing enterocolitis increased. Deaths within the first 12 hours after birth were mostly from immature development of body systems. Deaths after 12 hours were mostly from respiratory distress syndrome. Deaths from 15 to 60 days after birth were largely due to necrotizing enterocolitis, and deaths after 60 days were mostly from bronchopulmonary dysplasia.