Analytical study of factors determining success rate of trial of scar (TOS)

Abstract

Background: Cesarean section (CS) is the most commonly performed operation in modern obstetrics. To combat the increasing CS rates without facing any medicolegal controversies, one must be aware of the factors influencing the mode of delivery, intrapartum behavior, and associated maternal and fetal morbidity in these patients. This study is aimed for better understanding of these aspects, which would help in better patient selection during decision-making for mode of delivery. Objectives: To study the different factors affecting the mode of delivery including the indication of previous CS, success rate of trail of scar (TOS) in patients with previous CS. Materials and Methods: A prospective cohort study was carried out in the Department of Obsterics and Gyanecology, Shree Sayaji General (SSG) Hospital, Vadodara, India, from May 2011 to April 2012. All patients with previous lower segment CS admitted to SSGH (labor room and ward) were evaluated according to the protocol and pro forma of the study. Patients before 37 completed weeks of gestation with severe preeclampsia and ecalmpsia, severe anemia, and medical disorders (e.g., diabetes, heart disease) were excluded. Result: Of the 280 patients selected for the study, 165 delivered by a repeat CS and 115 had a vaginal birth after cesarean delivery (VBAC). Thus, incidence of VBAC was 41.07%. TOS was given to 160 patients (57.14%) with a success rate of 71.87%. While studying previous vaginal delivery, nonrecurrent indication of previous CS, dilation on admission >3 cm, adequate pelvis, faster average dilatation rate, augmentation of labor (p < 0.0001), and birth weight (p