Periviable infants are becoming more likely to survive without neurodevelopmental impairment

1. Periviable infants born from 2008-2011 survived to 18-22 months corrected age at a higher rate than those born from 2000-2003.

2. Rates of reaching 18-22 months corrected age without neurodevelopmental impairment were higher for periviable infants born during 2008-2011 compared to those born from 2000-2003.

Evidence Rating: 2 (Good)

Study Rundown: Periviable infants, born between 22 and 24 weeks of gestational age, are at greater risk of death and neurodevelopmental impairment despite medical advances in management and care. Recent studies have shown a decrease in mortality among periviable babies, though questions remain about the neurological development of these surviving infants. For families and clinicians to make better informed decisions, more information regarding survival and neurodevelopmental outcomes of these high risk infants are needed. This study sought to provide this information by following periviable infants across various time periods and assessing rates at which they displayed neurodevelopmental impairments.

Periviable infants born at tertiary care centers and included in a national research registry were subjects of this study. Infants were divided into epochs of 2000-2003, 2004-2007, and 2008-2011 to assess how the year of their birth correlated with their survival and neurological functional outcomes. All infants surviving to 18-22 months corrected age, the age an infant would be if born at term, were assessed for neurologic function. Those born during the most recent epoch were significantly more likely to survive than those born during the first epoch. Rates of survival without neurologic impairment were also higher for infants born most recently compared to those born in the earliest group.

Click to read the study, published in NEJM

Relevant Reading: Preterm babies at a glance

In-Depth [retrospective cohort]: Infants born at 11 academic tertiary care centers at a gestational age of 22 weeks to 24 weeks and 6 days between 2000 and 2011 were included in the research registry utilized for this study. Information regarding 4274 infants, their mothers, and medical care of the infants were included in the data registry. Outcomes assessed were survival, survival with neurodevelopmental impairment, and survival without neurodevelopmental impairment at 18-22 months corrected age, the age of an infant if born at term. Outcomes were compared across three epochs to assess for changes in outcomes over time: 2000-2003 (epoch 1, n = 1391), 2004-2007 (epoch 2, n = 1535), and 2008-2011 (epoch 3, n = 1348). Assessment of neurodevelopmental impairment was performed by neurologic examinations and the Bayley Scales of Infant and Toddler Development, with a definitive score cutoff defining a child and neurodevelopmental impaired or not. Infants survived at a higher rate in epoch 3 compared to epoch 1 (36% vs 30%, respectively; p < 0.001). Infants surviving without neurodevelopmental impairment increased significantly between epoch 1 and epoch 3 (16% vs 20%, respectively; p < 0.001). Surviving infants had similar rates of neurodevelopmental and neurosensory impairment across the 3 epochs. These improvements across time periods were speculated to be related to advanced obstetric and neonatal care, as significant declines were seen in rates of complications such as late-onset sepsis, severe retinopathy or prematurity, and postnatal glucocorticoid use.

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