Long-Term Outcomes of Small for Gestational Age Twins Born at 34 Weeks or Later

This article aims to compare long-term neurodevelopmental and health outcomes of twins born at 34 weeks or later, based on the presence of small for gestational age (SGA).

This study is a mail-based survey of twin gestations delivered by a single practice. We compared twins with and without SGA delivered at ≥34 weeks. There were two primary outcomes for this study: a composite of major adverse outcomes (death; cerebral palsy; necrotizing enterocolitis; chronic renal, heart, or lung disease) and a composite of minor adverse outcomes (learning disability, speech therapy, occupational therapy, physical therapy). Regression analysis was performed to control for clustering of outcomes within twin pairs.

A total of 712 children were included. Comparing twins with birthweights <10% to ≥10%, there were no significant differences in rates of composite major morbidities (3.2 vs. 1.4%, p = 0.109) or composite minor morbidities (43.6 vs. 39.3%, p = 0.279). Comparing twins with birthweights <5% to ≥5%, the rates of major morbidities were low in both groups, but significantly higher in the group with birthweights <5% (4.4 vs. 1.6%, p = 0.046). There were no significant differences seen in the composite minor morbidities (46.7 vs. 39.7%, p = 0.134). Twins with birthweights <5% were significantly more likely to have childhood cardiac disease (2.9 vs. 0.7%, p = 0.041).

Twins with SGA <10% born at ≥34 weeks have similar long-term neurodevelopmental and health outcomes compared with twins with normal birthweights. Birthweight less than 5th percentile is associated with an increased risk of major morbidity, specifically cardiac disease, but the absolute risk is low.