Are women who have had a preterm twin delivery at greater risk of a subsequent preterm delivery if pregnant with a singleton?

Abstract

OF A SUBSEQUENT PRETERM DELIVERY IF PREGNANT WITH A SINGLETON? FRANCESCA FACCO, KATE NASH, WILLIAM GROBMAN, Northwestern University, Chicago, Illinois, Northwestern University, Obstetrics/Gynecology, Chicago, Illinois OBJECTIVE: 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 followed by a singleton pregnancy at Northwestern Memorial Hospital between 6/1/1995 to 5/31/2005 were identified. Those women with a preterm delivery (less than 37 weeks) prior to the index pregnancy, or who delivered the index twin pregnancy prior to 20 weeks, iatrogenically preterm, or with a major fetal anomaly were excluded from further analysis. The women were then analyzed using a cohort study design, in which those whose twin delivery was preterm were compared with those whose twin delivery was term. Bivariable comparisons were made with the student t test and chi square analysis. RESULTS: One hundred and sixty-seven women were identified who delivered twins followed by a singleton and met the inclusion criteria. Ninety-nine (59%) of the initial twin deliveries were preterm. The women who delivered preterm twins were no different from those who delivered term twins with regard to age, race, significant past medical history, or number of prior term births. However, women who had delivered a preterm twin pregnancy were significantly more likely than those who had delivered a term twin pregnancy to deliver a subsequent preterm singleton pregnancy (13.1% versus 2.9%, odds ratio 5.0, 95% confidence interval 1.1, 22.9). CONCLUSION: Preterm birth of twins is associated with an increased risk of preterm delivery in a subsequent singleton pregnancy.