Adherence to criteria for transvaginal ultrasound imaging and measurement of cervical length

Jay D. Iams, William A. Grobman, Albina Lozitska, Catherine Y. Spong, George Saade, Brian M. Mercer, 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, Peter J. Van Dorsten