Sub-cohort of parous women
In the sub-cohort of 333,435 parous women, the aforementioned variables significantly associated with end-organ injury or death persisted, as did the addition of an unplanned caesarean delivery and severe organ injury in a previous birth (Table S6). The C-statistic was 0.61 (95% CI 0.59-0.63) when limited to variables from the index pregnancy (Figure 2a), rising to 0.69 (95% CI 0.67-0.70) after adding pre-pregnancy predictors (Figure 2b), and 0.71 (95% CI 0.69-0.73) when including the variables from a previous pregnancy (Figure 2c). We noted minimal overfitting for each CPM, with optimism-corrected C-statistics of 0.60 (95% CI 0.58-0.62), 0.68 (95% CI 0.66-0.70), and 0.70 (95% CI 0.69-0.72), respectively.