Standardized Criteria for Measuring Severe Maternal Morbidity in Placenta Accreta Spectrum Disorder.

Placenta accreta spectrum (PAS) is associated with significant maternal morbidity, but inconsistent outcome reporting across studies hampers meaningful comparisons of management approaches. This statement proposes standardized criteria for measuring severe maternal morbidity and mortality (SMM) for PAS, distinguishing true complications from expected interventions in care. Traditional SMM definitions are problematic for PAS research because they classify anticipated interventions such as hysterectomy and blood transfusions as complications. Through collaborative expert consensus, we identified outcomes that represent unexpected events with significant health consequences for inclusion in a composite primary outcome. The proposed SMM for PAS definition includes maternal death, transfusion of 8 or more units of packed red blood cells, unplanned return to the operating room, specific organ injuries, prolonged mechanical ventilation, pulmonary complications, acute renal failure, prolonged vasopressor use, circulatory support requirements, acute coronary syndrome requiring intervention, cardiac arrest, thromboembolism, and neurologic events. This composite outcome avoids bias toward specific management approaches, relies on objective criteria to limit interpretation variations, and excludes procedures reflecting institutional protocols rather than complications. By standardizing outcome reporting in PAS research, this definition aims to facilitate meaningful comparisons between studies, to generate evidence-based guidelines, and ultimately to improve patient care.