Mode of delivery of preterm twins.

At one high-risk perinatal centre over a 9-year period, 83.1% (103/124) sets of liveborn twins with gestational ages less than 33 weeks were delivered vaginally. Mortality in vaginal births was 26.7% (55/206), almost double that of Caesarean births of 14.3% (6/42), a non-significant difference. When gestational age discrepancies were corrected, however, the trend favouring survival of Caesarean births disappeared. Furthermore, there were no significant associations between mode of delivery and the condition of the infants at birth, or the presence of respiratory distress in the nursery. Because Caesarean section carries substantial risks for the mother our practice of predominantly vaginal deliveries for preterm twins should continue.