Significance of chorionicity on long-term outcome of low birthweight infants of <1500g in twin pregnancies

Aim: The aim of this study was to evaluate the long-term outcomes of very low birthweight twins by chorionicity and to identify the perinatal predictors for outcomes in the era of laser surgery for twin-twin transfusion syndrome. Material and Methods: This was a retrospective single-center cohort study of twin pregnancy infants <1500 g from 2003 through 2010. During the study period, laser surgery was performed on cases of twin-twin transfusion syndrome. The composite of adverse outcomes at 3 years of age was defined, including death, cerebral palsy, and developmental delay. The association between perinatal factors and adverse outcomes was evaluated by multiple logistic regression analysis. Results: A total of 162 infants (79 dichorionic diamniotic twins [DCDA] and 83 monochorionic diamniotic twins [MCDA]) were included in this study. Laser surgery was performed on 11 cases. The rate of adverse outcomes was 13.9% for DCDA and 26.5% for MCDA. The incidence of each outcome for DCDA and MCDA was: cerebral palsy, 1.3% and 4.8%; developmental delay, 8.9% and 9.6%; and death, 3.8% and 14.5%. Gestational age at birth (adjusted odds ratio: 0.69; 95% confidence interval, 0.57-0.84); and anemia at birth (adjusted odds ratio, 10.64; 95% confidence interval, 1.69-66.9) were independent risk factors, whereas chorionicity did not have significance for outcomes. Conclusion: The long-term outcome of very low birthweight MCDA was almost identical to that of DCDA. Gestational age and anemia at birth were independent risk factors for adverse outcomes.