Evaluation of the upper uterine cervix by the location of the vesicocervical fold of the urinary bladder to rule out cervical shortening during pregnancy with and without premature contractions. - Shalev, J.; Meizner, I.; Orvieto, R.; Mashiach, R.; Vardimon, D.; Hod, M.; Ben-Rafael, Z. (Ultrasound in Obstetrics & Gynecology, 1999)