Comparison of mortality and morbidity in multiple versus singleton very low birth weight infants in a neonatal intensive care unit

Multiple births in Korea have been increased recently as a consequence of increased infertility due to advancing maternal age at first birth, and increased use of assisted reproductive technology. Multiples suffer higher mortality and morbidity than singletons. However, it is not clear whether preterm multiple very low birth weight infants (VLBWI) suffer higher mortality and morbidity than comparable singletons. We evaluated 266 singleton and 113 multiple VLBWI to determine whether mortality and morbidity in multiple VLBWI were higher than those in comparable singletons. The rate of in vitro fertilization and cesarean section were significantly higher in multiples than singletons. The total and the adjusted mortality with gestational age and birth weight were not significantly different between the two groups. Maternal age and the incidence of respiratory distress syndrome, patent ductus arteriosus, bronchopulmonary dysplasia, intracranial hemorrhage (grade greater than or equal to3), cystic periventricular leukomalacia, and retinopathy of prematurity (stage greater than or equal to3) were not significantly different between the two groups, and the incidence of abnormal brainstem auditory evoked potential was higher among the singletons. These results suggest that multiple VLBWI do not suffer higher mortality or morbidity than comparable singletons.