Prediction and prevention of spontaneous preterm birth in twin gestations.

The incidence of twin gestation has increased significantly over the past 30 years. One of the most significant public health implications of this trend is the increased incidence of preterm birth (PTB). Efforts to improve neonatal outcomes must address the rate of PTB, particularly among multiple gestations, which contribute a disproportionate share to the burden of PTB and neonatal morbidity. There is evidence that sonographic cervical length assessment and fetal fibronectin testing can identify twin pregnancies at risk for PTB, but, to date, there are no proven interventions for prevention of PTB in this population. Perhaps the most promising is vaginal progesterone, which has been shown to reduce the risk of PTB in a cohort of women that included twin gestations. However, the study lacked statistical power to definitively answer this question. Identification of an appropriate treatment for twin gestations recognized to be at increased risk for prematurity will help to decrease overall rate of PTB, a significant public health problem in the United States.