Examining Cesarean Section Rates in Canada Using the Modified Robson Classification.

Objective: Canada's cesarean delivery (CD) rate continues to increase. The Society of Obstetricians and Gynaecologists of Canada advocates the use of the modified Robson classification for comparisons. This study describes national and provincial CD rates according to this classification system.

Methods: All 2016-2017 in-hospital births in Canada (outside Québec) reported to the Discharge Abstract Database were categorized using the modified Robson classification system. CD rates, group size, and contributions of each group to the overall volume of CD were reported. Rates by province and hospital peer group were also examined (Canadian Task Force Classification III).

Results: A total of 286 201 women gave birth; among these, 83 262 (29.1%) had CDs. Robson group 5 (term singleton previous CD) had a CD rate of 80.5% and was the largest contributing group to the overall number of CD (36.6%). Women whose labour was induced (Robson group 2A) had a CD rate almost double the rate of women with spontaneous labour (Robson group 1): 33.5% versus 18.4%. These latter two groups made the next largest contributions to overall CD (15.7% and 14.1%, respectively). There were substantial variations in CD rates across provinces and among hospital peer groups.

Conclusion: The study found large variations in CD rates across provinces and hospitals within each Robson group, thus suggesting that examining variations to determine the groups contributing the most to CD rates (Robson groups 5, 2A, and 1) may provide valuable insight for reducing CD rates. This study provides a benchmark for measuring the impact of future initiatives to reduce CD rates in Canada.