External validation of the Maternal Severity Index for predicting maternal death following potentially life-threatening complications during pregnancy and childbirth: a single-centre, prospective observational study.

The MSI has good discriminative performance in distinguishing who succumbs to life-threatening complications, but needs recalibration to avoid overfitting. SMR of less than 0.5 indicates fewer than expected deaths, suggesting good quality of care in reducing maternal mortality in the study population.