Have neurodevelopmental outcomes improved in extremely preterm children?

Medical advancements in perinatal and neonatal care have led to greater survival for extremely preterm infants. A report in JAMA Pediatrics examined whether these advances had also led improvements in the neurodevelopmental outcomes in children who were born <28 weeks’ gestation.¹

The investigators used 4 prospective longitudinal cohort studies that included all live extremely preterm births 22 to 27 weeks’ gestation in the state of Victoria, Australia in 1991-1992, 1997, 2005, and 2016-2017. The main outcomes looked at were survival, blindness, cerebral palsy, developmental delay, deafness, and neurodevelopmental disability at 2 years’ corrected age. Delays in development included a developmental quotient that was less than -1 SD relative to the control group averages on the Bayley Scales. A major neurodevelopmental disability involved moderate to severe cerebral palsy, blindness, deafness, or a developmental quotient less than −2 SDs.

Data were available for 1152 children across the 4 studies. The investigators found that survival to 2 years of age was highest in the 2016-2017 cohort (73% [215 of 293]) in comparison with the other cohorts: 1991-1992: 53% (225 of 428); 1997: 70% (151 of 217); 2005: 63% (170 of 270). Additionally, cerebral palsy was not as common in 2016-2017 (6%) than the other 3 time periods (1991-1992: 11%; 1997: 12%; 2005: 10%). No notable changes in the rates of developmental quotient less than -2 SDs (1991-1992: 18%; 1997: 22%; 2005: 7%; 2016-2017: 15%) or rates of major neurodevelopmental disability (1991-1992: 20%; 1997: 26%; 2005: 15%; 2016-2017: 15%) were found across the eras. Across all 4 cohorts, both blindness and deafness were not common. Furthermore, the rate of survival that was also free from major neurodevelopmental disability went up steadily over time 42% (1991-1992), 51% (1997), 53% (2005), and 62% (2016-2017) (odds ratio, 1.30; 95% CI, 1.15-1.48 per decade; P < .001).

The investigators concluded that children who are born extremely preterm are increasingly surviving to age 2 years without a major disability. Furthermore, this increased rate of survival was not linked to an increase in neurodevelopmental disability.

Reference

1. Cheong J, Olsen J, Lee K, et al. Temporal trends in neurodevelopmental outcomes to 2 years after extremely preterm birth. JAMA Pediatr. July 19, 2021. Epub ahead of print. doi:10.1001/jamapediatrics.2021.2052