Neonatal morbidity in second twin according to gestational age at birth and mode of delivery

Objective This study was undertaken to assess the risk of neonatal morbidity in the second twins. Study design We carried out a cohort study of 128,219 live born second twins in the United States, 1995 through 1997. The study subjects were divided into 3 groups: second twins delivered by cesarean section after vaginal delivery of the first twin (V-C), both twins delivered vaginally (V-V), and both twins delivered by cesarean section (C-C). Results The rates of low 5-minute Apgar score, mechanical ventilation, and seizure were higher in the V-C group (8.27%, 13.39%, and 0.31%) than in the V-V (3.07%, 7.51%, and 0.08%) and the C-C (2.66%, 8.53%, and 0.06%) groups. The V-C associated increase in risk remained after adjustment for confounding factors and was more evident at term than preterm. Conclusion The risk of neonatal morbidity is increased in second twins who had a cesarean section after vaginal delivery of the first twin, especially at term.