The aim was to investigate maternal background factors' significance in relation to risk of elective and emergency caesarean sections (CS) in Sweden.Population-based, retrospective, cross-sectional study. The Swedish Maternal Health Care Register (MHCR) is a national quality register that collects data on pregnancy, delivery and postpartum period. All women registered in MHCR 2011 to 2012 were included in the study sample (N = 178,716).The risk of elective and emergency caesarean section in relation to age, parity, education, country of origin, weight in early pregnancy and weight gain during pregnancy was calculated in logistic regression models.Multiparous women demonstrated a doubled risk of elective CS compared to primiparous women, but their risk for emergency CS was halved. Overweight and obesity at enrolment in antenatal care increased the risk for emergency CS, irrespective of parity. Weight gain above recommended international levels (Institute of Medicine, IOM) during pregnancy increased the risk for emergency CS for women with normal weight, overweight or obesity.There is a need of national guidelines on recommended weight gain during pregnancy in Sweden. We suggest that the usefulness of the IOM guidelines for weight gain during pregnancy should be evaluated in the Swedish context.