TY - JOUR AU - Wing, D A; Szychowski, J; Owen, J; Vaginal Ultrasound Trial Consortium TI - Gestational age at previous preterm birth does not affect cerclage efficacy JO - Am J Obstet Gynecol IS - 04 VL - 203 PY - 2010 DO - 10.1016/j.ajog.2010.05.018 L3 - PubMed-ID: 20579957 SP - 377.e1 EP - 377.e4 ER -