Diabetes in pregnancy may differentially affect neonatal outcomes for twins and singletons.

Aim: We tested the hypothesis that diabetes in pregnancy may differentially affect neonatal outcomes in twin vs. singleton pregnancies.

Methods: In a retrospective cohort analysis of twins (n = 422 068) and singletons (n = 14 298 367) born in the USA from 1998 to 2001, we evaluated the adjusted odds ratios of adverse neonatal outcomes comparing diabetic vs. non-diabetic pregnancies, controlling for maternal characteristics. Primary outcomes include macrosomia (birthweight for gestational age > 90th percentile), congenital anomalies, low 5-min Apgar score (< 4) and neonatal death.

Results: Diabetes in pregnancy was associated with a similarly increased risk of congenital anomalies (adjusted odds ratios 1.52 vs. 1.59) and smaller increased risks of preterm birth (adjusted odds ratios 1.27 vs. 1.49) and macrosomia (adjusted odds ratios 1.38 vs. 2.03) in twins vs. singletons, but reduced risks of low 5-min Apgar score (adjusted odds ratio 0.74) and neonatal death (adjusted odds ratio 0.76) in twins but not singletons.

Conclusions: Diabetes in pregnancy may differentially affect neonatal outcomes in twins and singletons, indicating a need for further studies to differentiate the effects by clinical subtypes of diabetes in pregnancy, and to consider/evaluate differential clinical management protocols of diabetes in multiple vs. singleton pregnancies.