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NIH: Survival, neurodevelopmental outcomes improve among extremely preterm infants

Survival rates for very early preterm infants increased slightly from 2000 to 2011, and these infants were less likely to have neurological or developmental impairment, according to an analysis by the NIH published in the New England Journal of Medicine.

“Care of periviable infants remains a great challenge in neonatal and perinatal medicine,” Noelle Younge, MD, MHS, from the department of pediatrics at Duke University, and colleagues wrote. “Infants born between 22 and 24 weeks of gestation often die or survive with long-term neurodevelopmental impairment. The approach to resuscitation and management at these early gestational ages varies substantially.”

“Data reported during the past 5 years indicate that rates of survival have increased among infants born at the borderline of viability, but less is known about how increased rates of survival among these infants relate to early childhood neurodevelopmental outcomes,” they added.

To address this lack of information, Younge and colleagues evaluated changes over time in survival and neurodevelopmental outcomes among infants born at 22 to 24 weeks of gestation. They examined these outcomes at 18 to 22 months of corrected age, defined as the age the infant would be if born at term. Changes were assessed across three consecutive birth-year epochs: 2000 to 2003, 2004 to 2007 and 2008 to 2011. The researchers compared the relative risk of survival without neurodevelopmental impairment, survival with neurodevelopmental impairment and death using multinomial generalized logit models while adjusting for differences in infant characteristics. The analysis included 4,274 infants born at 11 centers from the NIH research network.

From 2000 to 2011, survival for very early preterm infants increased from 30% to 36% and survival without neurodevelopmental impairment increased from 16% to 20% — a small but significant increase. However, there was no significant change in the survival rate of infants born with neurodevelopmental impairment (15% in 2000 vs. 16% in 2011). In comparison to death, there was an increase over time in the rate of survival with neurodevelopmental impairment (adjusted RR = 1.27; 95% CI, 1.01-1.59) and the rate of survival without neurodevelopmental impairment (adjusted RR = 1.59; 95% CI, 1.28-1.99).

The researchers noted that despite these improvements, extremely preterm infants still have a high incidence of death, neurodevelopmental impairment and other adverse effects. They suggest that the improvements in overall survival and survival without neurological harm may reflect advances in obstetrical and neonatal care, such as broader use of antenatal drugs that can help an at-risk infant’s lungs mature, thus lessening the need for ventilation therapy with can damage the lungs or lead to infections.

“Our study provides important information for physicians and family members planning the care of these extremely fragile newborns,” coauthor Rosemary Higgins, MD, from NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development, said in a press release.

“Every individual is different, and no single source of information can precisely predict a baby’s chances of survival or disability,” she added. “But our study’s findings do provide important information that physicians and family members can consult to help determine treatment strategies.”

A previous study reported that 25% of extremely preterm infants survive without severe complications. – by Alaina Tedesco

Disclosure: The researchers report primary funding from the NIH.