National Variation in Caesarean Section Rates: A Cross Sectional Study in Ireland

Objective: Internationally, caesarean section (CS) rates are rising. However, mean rates of CS across providers obscure extremes of CS provision. We aimed to quantify variation between all maternity units in Ireland. Methods: Two national databases, the National Perinatal Reporting System and the Hospital Inpatient Enquiry Scheme, were used to analyse data for all women delivering singleton births weighing ≥500g. We used multilevel models to examine variation between hospitals in Ireland for elective and emergency CS, adjusted for individual level sociodemographic, clinical and organisational variables. Analyses were subsequently stratified for nullipara and multipara with and without prior CS. Results: The national CS rate was 25.6% (range 18.2% ─ 35.1%). This was highest in multipara with prior CS at 86.1% (range 6.9% ─ 100%). The proportion of variation in CS that was attributable to the hospital of birth was 11.1% (95% CI, 6.0 ─ 19.4) for elective CS and 2.9% (95% CI, 1.4 ─ 5.6) for emergency CS, after adjustment. Stratifying across parity group, variation between hospitals was greatest for multipara with prior CS. Both types of CS were predicted by increasing age, prior history of miscarriage or stillbirth, prior CS, antenatal complications and private model of care. Conclusion: The proportion of variation attributable to the hospital was higher for elective CS than emergency CS suggesting that variation is more likely influenced by antenatal decision making than intrapartum decision making. Multipara with prior CS were particularly subject to variability, highlighting a need for consensus on appropriate care in this group.