Among periviable infants born at 11 tertiary care centers in 2000 through 2011, the rate of survival without neurodevelopmental impairment increased a small but significant 4%, according to a report published online Feb. 16 in the New England Journal of Medicine.

The rate of survival with neurodevelopmental impairment also increased, although to a lesser extent (1%).

The rise in the survival rate of these extremely premature infants born at 22-24 weeks’ gestation “was not associated with a disproportionate increase in the rate of survival with neurodevelopmental impairment; rather, the rate of survival without neurodevelopmental impairment and the rate of survival with neurodevelopmental impairment increased similarly (adjusted relative risk, 1.27),” said Noelle Younge, MD, and her associates in the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network.

“These findings are important for guiding counseling and decision making with respect to periviable birth. Prognosis continues to be guarded; in the most recent epoch [time period in our study], mortality was 64%, and 43% of surviving infants had neurodevelopmental impairment,” they noted.

The investigators defined such impairment as moderate or severe cerebral palsy, Gross Motor Function Classification System level of at least 2 on a scale of 1-5, profound hearing loss requiring amplification in both ears, profound visual impairment in both eyes, or cognitive impairment such as a Mental Developmental Index score of less than 70 or a Cognitive Composite score of less than 85.

To examine time trends in the outcomes of periviable infants, Dr. Younge of Duke University, Durham, N.C., and her associates analyzed data from the network’s registry of births at 11 academic tertiary care centers nationwide. They focused on 4,274 infants who were born during 3 epochs – 2000-2003, 2004-2007, and 2008-2011 – and were evaluated for motor function, sensory impairment, and cognitive delay at a corrected age of 18-22 months.

The percentage of infants who survived without neurodevelopmental impairment increased over time, from 16% during the first epoch to 20% during the third epoch. However, the percentage who survived with neurodevelopmental impairment also increased, from 15% during the first epoch to 16% during the third epoch (New Engl. J. Med. 2017 Feb 16. doi: 10.1056/NEJMoa1605566 ).

The rates of active treatment of these periviable infants didn’t change significantly over time. Overall, 22% of infants born at 22 weeks, 71% of those born at 23 weeks, and 95% of those born at 24 weeks received active treatment at birth. Therefore, the overall decrease in mortality and the 4% improvement in neurodevelopmental outcomes wasn’t attributable to greater use of active treatment for periviable infants over time, said Dr. Younge and her associates.

Despite these small but significant improvements in outcomes, “the incidence of death, neurodevelopmental impairment, and other adverse outcomes remains high in this population,” they noted.

This study was supported by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the National Institutes of Health, the National Center for Research Resources, and the National Center for Advancing Translational Sciences for the Neonatal Research Network’s Generic Database and Follow-up Studies. Dr. Younge reported having no relevant financial disclosures; two of her associates reported ties to Pediatrix Medical Group and rEVO Biologics.


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