Discordant and nondiscordant twins: comparative multimethod risk assessment in the neonatal period.

Full-term neonate twins from weight-discordant pairs were compared with nondiscordant pairs on perinatal variables, minor physical anomalies, developmental status, and temperament/interactive measures. For perinatal variables, twins from the top quartile of discordance were found to be at higher risk than other twins. Both the total group of discordant twins and twins with the most extreme discordance had higher weighted minor physical anomaly scores, more minor physical anomalies, and lower developmental status scores than nondiscordant twins. For temperament, twins in the extreme discordant group were more active while awake than twins in the nondiscordant group. The results are discussed in relation to expected group differences in perinatal measures, the timing during gestation of insults related to discordance and minor physical anomalies, and the significance of behavioral differences between cotwins versus between groups. Implications for developmental risk for both twins from discordant pairs are discussed.