Prediction of spontaneous preterm birth among nulliparous women with a short cervix

William A. Grobman, Yinglei Lai, Jay D. Iams, Uma M. Reddy, Brian M. Mercer, George Saade, Alan T. Tita, Dwight J. Rouse, Yoram Sorokin, Ronald J. Wapner, Kenneth J. Leveno, Sean C. Blackwell, M. Sean Esplin, Jorge E. Tolosa, John M. Thorp, Steve N. Caritis