Objective: To identify risk factors of cesarean section due to cephalopelvic disproportion
Setting: Department of Obstetrics and Gynecology, Faculty of Medicine, Siriraj Hospital
Study Design: Case-control study
Material and Method: One hundred and three singleton, viable, term pregnant women in cephalic presentation delivered by cesarean section due to cephalopelvic disproportion (CPD) and 105 controls gave normal birth just before or after the study case. Demographic, anthropometric data, labor characteristics, and neonatal outcomes were obtained from medical records. The expected risk indicators of the case and control groups were compared by using independent unpaired T-test and exact probability test as appropriate. Multiple logistic regression analysis was used to determine the significant risk factors (p < 0.05).
Results: Significant independent risk factors of cesarean section due to CPD were: estimated fetal weight (EFW) > 3,000 g (OR = 3.96, 95%CI = 2.06, 7.63), pre-pregnancy BMI > 25 kg/m2 (OR = 5.06, 95%CI = 1.67, 15.34), nulliparity (OR = 2.98, 95%CI = 1.31, 6.78) and the inadequacy of clinical pelvimetry (OR = 8.49, 95%CI = 1.01, 71.78), (p < 0.05).
Conclusion: Risk factors for cesarean section due to CPD were EFW > 3,000 g, pre-pregnancy BMI > 25 kg/m2, nulliparity and the inadequacy of clinical pelvimetry. They are useful in the categorization of individual women into high and low CPD-risk groups.

Keywords: Risk factors, Cephalopelvic disproportion, Cesarean section