Survival Rate May Be Improving for Extremely Preterm Infants
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. A study appearing in the New England Journal of Medicine (2017; 376:617-628) has shown that very early preterm infants are more likely to survive than in previous years, and the survivors are less likely to have neurological problems. The study found that of the more than 4,000 infants born at 11 sites within the network from 2000 to 2011, survival rates increased from 30% to 36%, and the proportion of survivors who did not have a neurological or developmental impairment increased from 16% to 20%. The authors theorize that these improvements are a result of advances in the care provided to expectant mothers and their newborns.
Infants in the study were born between the 22nd and 24th week of pregnancy, far earlier than the 40 weeks generally expected for a pregnancy to reach term. Those born from 2008 to 2011 had the lowest death rate (64%). From 2004 to 2007, the death rate was 70%, unchanged from 2000 to 2003.
According to the authors, the results encompass trends for a large number of infants at multiple research sites, but they should not be used to predict the outcome for an individual child. In addition, providing care to infants born so early is often challenging. Physicians and family members can be reluctant to expose an infant to sometimes painful life-support procedures. Those offered active treatment may survive, but may have hearing loss, blindness, cerebral palsy, and severe intellectual disability. The authors added that in the past, many experts had feared that advances leading to improvements in survival among extremely preterm infants might also result in a higher proportion of infants with disabilities. However, in the current study, it was found that across all three time intervals, the percentage of infants who survived with a disability did not change significantly. Finally, the authors wrote that the increases in overall survival and survival without neurological harm likely result from improvements in the care given to mothers and newborns. One potential contributing factor is the wider use of antenatal steroids. These drugs, which are given to women at risk for preterm birth, help the infant’s lungs mature, leaving the infant less reliant on ventilation therapy, which can sometimes damage the lungs and lead to infections.