The role of maternal body mass index in outcomes of vaginal births after cesarean Emmanuel Bujold, MD, a Ahmad Hammoud, MD, a Christiane Schild, MD, b Martin Krapp, MD, b Peter Baumann, MD a, * Department of Obstetrics and Gynecology, Hutzel Hospital, Wayne State University, Detroit, MI a ; Department of Obstetrics and Gynecology, Medical University Lu ¨beck, Lu ¨beck, Germany b Received for publication December 17, 2004; revised March 4, 2005; revised March 19, 2005 KEY WORDS Body mass index Vaginal birth after prior cesarean Obesity Objective: To evaluate the association between maternal body mass index and obstetrical outcome in patients with a prior cesarean undergoing a trial of labor versus elective repeat cesarean. Study design: A perinatal database between 1991 and 1997 was used to identify secundipara at term after a previous cesarean section. In different groups according to maternal body mass index, the rates of successful vaginal birth after caesarean, uterine scar separation, and other obstetrical outcomes were evaluated. Results: Of 8580 patients with a prior cesarean, 1862 (21.7%) underwent an elective repeat cesarean and 6718 (78.3%) underwent a trial of labor. Maternal body mass index correlated inversely with the rate of successful vaginal birth after caesarean but not with the rate of uterine scar separation. After adjustment for confounding factors including maternal age, birth weight, induction of labor, and preeclampsia, maternal body mass index remained associated with a lower rate of successful vaginal birth after cesarean. Conclusion: Maternal body mass index is an independent factor associated with a lower rate of successful vaginal birth after cesarean. Ó 2005 Mosby, Inc. All rights reserved. Until recently standard of obstetrical care was to routinely offer a trial of labor to patients with a prior cesarean section. New research has suggested that there is a potential risk for uterine rupture and that the associated neonatal and maternal morbidity may be higher than what has been thought in some subgroups of patients. When compared with patients electing a repeat cesarean, patients who undergo a successful trial of labor have lower rates of maternal morbidities. 1 However, a failed trial of labor is associated with a 5-fold increase in major maternal morbidities when compared with elective repeat cesarean. 1 Appropriate patient selection with a high likelihood of successful vaginal birth after cesarean (VBAC) is therefore crucial for successful outcomes. To date, the impact of obesity on labor in patients with a prior cesarean has been poorly studied with only few studies with limited Presented as a poster at the 71st Annual Meeting of the Central Association of Obstetrics and Gynecology, October 13-16, 2004, Washington, DC. * Reprint requests: Peter Baumann, MD, Department of Obstetrics and Gynecology, Hutzel Women’s Hospital, Wayne State University, 3990 John R., 7 Brush North, Detroit, Michigan 48201. E-mail: pbaumann@med.wayne.edu 0002-9378/$ - see front matter Ó 2005 Mosby, Inc. All rights reserved. doi:10.1016/j.ajog.2005.03.041 American Journal of Obstetrics and Gynecology (2005) 193, 1517–21 www.ajog.org