Table 1 Original versus Extended fullPIERS Logistic Regression Equations for the prediction of adverse maternal outcomes from pre-eclampsia

logit (pi) = 2·68 + (− 5·41 × 10^− 2; gestational age at eligibility) + 1·23(chest pain or dyspnea)+

(− 2·71 × 10^− 2; creatinine) + (2·07 × 10^− 1; platelets) + (4·00 × 10^− 5; platelets²)+

(1·01 × 10^− 2; aspartate transaminase (AST))+

(− 3·05 × 10^− 6; AST²) + (2·50 × 10^− 4; creatinine×platelet) + (− 6·99 × 10^− 5; platelet×AST) + (− 2·56 × 10^− 3; platelet×SpO₂)

logit (pi) = − 1.34 + (0.25 × fullPIERS model linear predictor) + (− 0.01 × PlGF)

Odds ratio (adverse maternal outcome) = 0.26 + (1.28 × fullPIERS model linear predictor [95% CI 1.23–1.33]) + (0.99 × PlGF [95% CI 0.98–0.99])