To assess the potential associations between social determinants of health (SDH) and severe maternal outcomes (SMO), to better understand the social structural framework and the contributory, non-clinical mechanisms associated with SMO. Prospective observational study. Tertiary referral centre in south-eastern region of India. One thousand and thirty-three women with potentially life-threatening complications (PLTC) were identified using WHO criteria. Social Determinants of Health (SDH). Severe maternal outcomes, which include maternal near-miss and maternal death. Logistic regression to assess the association between SDH and clinical factors on SMO, expressed as adjusted ORs (aOR) with a 95% CI. Of the 37 590 live births, 1833 (4.9%) sustained PLTC, and 380 (20.7%) developed SMO. Risk of SMO was higher with increasing maternal age (adjusted OR (aOR) 1.04 (95% CI 1.01 to 1.07)), multiparity (aOR 1.44 (1.10 to 1.90)), medical comorbidities (aOR 1.50 (1.11 to 2.02)), obstetric haemorrhage (aOR 4.63 (3.10 to 6.91)), infection (aOR 2.93 (1.83 to 4.70)), delays in seeking care (aOR 3.30 (2.08 to 5.23)), and admissions following a referral (aOR 2.95 (2.21 to 3.93)). SMO was lower in patients from socially backward community (aOR 0.45 (0.33 to 0.61)), those staying more than 10 km from hospital (aOR 0.56 (0.36 to 0.78)), those attending at least four antenatal visits (aOR=0.53 (0.36 to 0.78)) and those referred from resource-limited facilities (aOR=0.62 (0.46 to 0.84)). This study demonstrates the independent contribution of SDH to SMO among those sustaining PLTC in a middle-income setting, highlighting the need to formulate preventive strategies beyond clinical considerations.