Are women who have had a preterm twin delivery at greater risk of preterm birth in a subsequent singleton pregnancy?

Objective: The purpose of this study was to determine whether preterm birth of twins is associated with an increased risk of preterm birth in a subsequent singleton pregnancy. Study Design: All patients who delivered a twin gestation and a subsequent singleton pregnancy at Northwestern Memorial Hospital during a 10-year period were identified. We used a cohort study design, comparing the outcomes of the singleton pregnancies in women with preterm twin deliveries to those pregnancies with term twin deliveries. Results: One hundred sixty-seven women delivered twins followed by a singleton pregnancy. Women whose twin delivery was preterm (n = 99) were more likely than those who had delivered a term twin pregnancy (n = 68) to deliver a subsequent preterm singleton pregnancy (13.1% vs 2.9%; odds ratio, 5.0; 95% CI, 1.1, 22.9). Conclusion: Preterm birth of twins is associated with an increased risk of preterm delivery in a subsequent singleton pregnancy.