Association between small-for-gestational-age and neurodevelopmental impairment at two years of life among infants born at preterm gestational ages

OBJECTIVE: To investigate the effect of small-for-gestational-age (SGA) on neurodevelopmental outcomes at two years of life among infants born at preterm gestational ages. STUDY DESIGN: This was a secondary analysis of Maternal-Fetal Medicine Units Network study assessing the effect of antepartum magnesium sulfate on adverse neonatal outcomes among women at risk for preterm delivery at <32 weeks (BEAM trial). Non-anomalous pregnancies delivered at preterm gestational ages (<37 weeks) were included in the analysis. Neurodevelopmental outcomes at 2 years of life were compared between infants who were SGA at birth vs. appropriately grown (AGA). The primary outcomes were moderate to severe neurological injury at 2 years of life defined as mental developmental index (MDI) <85 and MDI <70; secondary outcomes included cerebral palsy (CP) at 2 years and death after discharge. Multivariable regression modeling was used to investigate the association between SGA and significant outcomes. RESULTS: We identified 2,299 preterm infants who met inclusion criteria; of those 67 (3%) were SGA at birth. No significant differences were found in maternal characteristics including age, race, BMI, parity or smoking between the SGA vs. AGA groups. SGA infants were more often twins (31% vs. 17%, p=0.003) and delivered more often via cesarean (63% vs. 40%, p<0.001) at similar gestational ages (30.0+/-2.6 vs. 29.5+/-2.8 weeks). There were more fetal and neonatal deaths in the SGA group (22% vs. 7%, p<0.001) and the association remained after adjustment for twin pregnancy (OR=3.5, 95%CI:1.9-6.2). At 2 years of life, SGA and AGA survivors had similar MDI scores (MDI <70: 12% vs. 14%, MDI <85: 30% vs. 37%), and CP rates (3% vs. 5%). Mortality after discharge (5% vs. 1%) was similar as well. (Table) CONCLUSION: In our cohort, there was increased fetal and neonatal mortality among preterm SGA infants, with similar neurodevelopmental outcomes at two years of life among survivors. These data deserve additional study in larger cohorts. (Table Presented).