Maternal Weight and the Success of Trial of Vaginal Delivery after Caesarean Section

Objective: To study the effect of maternal weight on the success of trial of vaginal delivery in women with previous one transverse lower segment caesarean section.Design: Prospective analytic study.Setting: The study is carried out in Ulster Hospital, a district general hospital in Northern Ireland.Material and Methods: A total of 218 women with a previous one caesarean section eligible for trial of labour were identified in the year 2008. All data were collected including height, weight, BMI, antenatal course, intrapartum and postpartum events. Women were classified into normal weight (BMI 20-24.9kg/m²), overweight (BMI 25-29.9kg/m²) and obese (BMI 30kg/m²).Results: Overall vaginal delivery rate was 64.2% (67.6%, 67.8% and 52.9% in the normal, overweight and obese groups respectively). Induction of labour (IOL) carried out a higher risk for caesarean section (CS) compared to the spontaneous onset of labour (45.6% versus 32.3% CS rate respectively). Hypertensive disorders complicating pregnancy complicated 71.4% of obese women. Diabetes mellitus/impaired glucose tolerance test complicated 19.6% of cases in the obese group. Notably in the post partum period, wound infection complicated 37.5% of cases in the obese group. Neonatal weight was significantly higher in the obese group.Discussion: Complicated antenatal course and certain complications in the peripartum period are more common in obese women. Counselling these women who had a previous caesarean section regarding the likelihood of achieving a vaginal delivery is crucial. Obese women whom their pregnancy is complicated by a medical problem are less likely to successfully have a vaginal delivery especially if labour has been induced.