Incidence of Preeclampsia and Cesarean Section Rate According to the Robson Classification.

Objectives The objective of this study was to determine the incidence of preeclampsia and associated cesarean section (CS) rate according to the Robson classification. Methods A retrospective cross-sectional study was conducted on a total of 670 women who delivered at a tertiary care hospital in Thailand during January to March 2023. All women were classified into 10 groups according to the Robson classification, and preeclampsia was identified. Overall and group-specific incidence of preeclampsia and CS rate were estimated. Comparison of CS rate was made between those with and without preeclampsia using the Chi-squared test. Relative risks (RR) and corresponding 95% confidence intervals were estimated. Results The majority of women were in group 1 (34%) and group 3 (30.7%). Overall CS rate was 40.6% with highest contribution from group 1, 5, and 10. Incidence of preeclampsia was 9.1%, and the majority were in groups 10 (29.5%) and 1 (23%). Preeclampsia significantly increased the rate of overall CS (RR 1.8, p<0.001). The risk of CS significantly increased in group 1 (RR 1.8, p=0.043), group 3 (RR 3.5, p=0.025), and group 10 (RR 1.9, p=0.006). Preeclampsia accounted for 15.4% of all CS, with the highest contribution in group 2 (37.5%), group 10 (31.1%), group 3 (16.7%), and group 1 (10.8%). Without preeclampsia, the overall CS rate was relatively reduced by 6.9%, with the largest relative reduction in group 10 (14.3%), group 3 (11.5%), group 2 (6.3%), and group 1 (5.2%). Conclusion The incidence of preeclampsia was 9.1%, and preeclampsia significantly increased the rate of overall CS. Without preeclampsia, overall CS rate relatively reduced by 6.9% but did not significantly change the relative contribution of CS according to the Robson classification.