Neuromorbidity in preterm twins in relation to chorionicity and discordant birth weight

Objective The purpose of this study was to determine the incidence of neurologic morbidity in preterm monochorionic (MC) and dichorionic (DC) twins. Study design We collected perinatal, neonatal, and infant follow-up data of 76 MC and 78 DC twins born between 24 and 34 weeks of gestation (295 infants). Risks of neuromorbidity in the surviving infants were evaluated in relation to chorionicity, discordant birth weight (>20%), twin-twin transfusion syndrome (TTTS), and cotwin death. Results The overall incidence of cerebral palsy and minor neurologic disabilities in surviving twins was 4% and 9%, respectively. MC infants had a higher incidence of cerebral palsy (8% vs 1%, P<.05) and neurologic morbidity (15% vs 3%, P<.05) than DC infants. The risk of impaired neurodevelopment was higher in MC infants with discordant birth weight (42%, P<.01), TTTS (37%, P<.01), and cotwin death (60%, P<.01) than those with concordant birth weight (8%). In MC pregnancies, the cerebral palsy risk was higher in infants with discordant birth weight than those with chronic TTTS (19% vs 4%, P<.05). Similarly, discordant DC infants had higher neuromorbidity than concordant group (5% vs 1%, P<.05). In both MC and DC discordant infants, neurologic morbidity was independent of growth restriction. Conclusion Neurologic morbidity in the preterm MC infants was 7-fold higher than DC infants because of chronic TTTS, discordant birth weight, and cotwin death in utero.