Objective: To assess the incremental value of blood oxygen saturation (SpO 2) as a predictor in the miniPIERS model, a risk prediction model for adverse outcomes among women with a diagnosis of hypertensive disorder of pregnancy (HDP) in low-resourced settings . Methods: Using data from a prospective cohort including 852 women admitted to hospital for a HDP, the association between SpO 2 and adverse maternal outcome was assessed using logistic regression . The miniPIERS model was recalibrated and extended to include SpO 2 . The incremental value of adding SpO 2 to the model was measured using a net reclassification index (NRI), sensitivity, specificity, positive and negative predictive values, and likelihood ratios . Results: SpO 2 of < 93% was associated with a 30-fold increase in risk (95% CI 14 to 68) of adverse maternal outcome compared to women with SpO 2 > 97% . After recalibration and extension, the miniPIERS model including SpO 2 (vs . not including SpO 2) had improved sensitivity (32 .8% vs . 49 .6%) at the cost of minimally decreased specificity (91.5% vs. 96.2%) with a NRI of 0.122.