Maternal mortality and severe morbidity associated with low-risk planned cesarean delivery versus planned vaginal delivery at term

• Published in: Canadian Medical Association journal 2007-02, Vol.176 (4), p.455-460
• Main Authors: Liu, Shiliang, Liston, Robert M, Joseph, K.S, Heaman, Maureen, Sauve, Reg, Kramer, Michael S, Maternal Health Study Group of Canadian Perinatal Surveillance System
• Format: Article
• Language: English
• Subjects: Adult; Breech Presentation; Canada - epidemiology; Case-Control Studies; Cesarean section; Cesarean Section - mortality; Cesarean Section - utilization; Comparative analysis; Delivery, Obstetric - standards; Delivery, Obstetric - trends; Elective Surgical Procedures - standards; Elective Surgical Procedures - trends; Female; Health aspects; Health Services Research; Humans; Incidence; Infant, Newborn; Maternal Age; Maternal Mortality - trends; Morbidity; Mortality; Mothers; Natural Childbirth; Obstetric Labor Complications - mortality; Patient Care Planning - standards; Patient Care Planning - trends; Patient outcomes; Pregnancy; Pregnant women; Probability; Reference Values; Risk Assessment; Studies; Survival Analysis; Term Birth; Womens health
• ISSN: 0008-4409; 0820-3946; 1488-2329
• DOI: 10.1503/cmaj.060870

The rate of elective primary cesarean delivery continues to rise, owing in part to the widespread perception that the procedure is of little or no risk to healthy women. Using the Canadian Institute for Health Information's Discharge Abstract Database, we carried out a retrospective population-based cohort study of all women in Canada (excluding Quebec and Manitoba) who delivered from April 1991 through March 2005. Healthy women who underwent a primary cesarean delivery for breech presentation constituted a surrogate "planned cesarean group" considered to have undergone low-risk elective cesarean delivery, for comparison with an otherwise similar group of women who had planned to deliver vaginally. The planned cesarean group comprised 46,766 women v. 2,292,420 in the planned vaginal delivery group; overall rates of severe morbidity for the entire 14-year period were 27.3 and 9.0, respectively, per 1000 deliveries. The planned cesarean group had increased postpartum risks of cardiac arrest (adjusted odds ratio [OR] 5.1, 95% confidence interval [CI] 4.1-6.3), wound hematoma (OR 5.1, 95% CI 4.6-5.5), hysterectomy (OR 3.2, 95% CI 2.2-4.8), major puerperal infection (OR 3.0, 95% CI 2.7-3.4), anesthetic complications (OR 2.3, 95% CI 2.0-2.6), venous thromboembolism (OR 2.2, 95% CI 1.5-3.2) and hemorrhage requiring hysterectomy (OR 2.1, 95% CI 1.2-3.8), and stayed in hospital longer (adjusted mean difference 1.47 d, 95% CI 1.46-1.49 d) than those in the planned vaginal delivery group, but a lower risk of hemorrhage requiring blood transfusion (OR 0.4, 95% CI 0.2-0.8). Absolute risk increases in severe maternal morbidity rates were low (e.g., for postpartum cardiac arrest, the increase with planned cesarean delivery was 1.6 per 1000 deliveries, 95% CI 1.2-2.1). The difference in the rate of in-hospital maternal death between the 2 groups was nonsignificant (p = 0.87). Although the absolute difference is small, the risks of severe maternal morbidity associated with planned cesarean delivery are higher than those associated with planned vaginal delivery. These risks should be considered by women contemplating an elective cesarean delivery and by their physicians.