Etiologies and Outcomes of Pregnancy-Related AKI in a US Quaternary Obstetric Population: A Retrospective Cohort Study

Background: Pregnancy-related acute kidney injury (PRAKI) is a serious complication with implications for both maternal and fetal health. While data from low-resource settings are abundant, limited evidence exists from high-income health systems. This study evaluated the risk factors and clinical outcomes associated with PRAKI in a large obstetric cohort at a U.S. quaternary care center. Methods: We performed a retrospective cohort study of 42,000 deliveries within the Mayo Clinic network. A validated electronic screening tool identified AKI cases based on serum creatinine and, when available, urine output. We compared maternal characteristics, comorbidities, and outcomes between patients with and without AKI. Primary outcomes included major adverse kidney events (MAKE: death, persistent kidney dysfunction, or dialysis at 30/90 days). Secondary outcomes included neonatal ICU (NICU) admissions and long-term maternal dialysis or infertility. Results: Among 29,586 obstetric patients, 341 (1.15%) developed AKI. Patients with AKI were older (30.3 vs. 29.3 years, p=0.004), had higher comorbidity burden (Charlson 0.56 vs. 0.19, p<0.0001), and earlier deliveries (255 vs. 272 days, p<0.0001). Chronic hypertension (28.7% vs. 5.2%) and gestational hypertension (37.8% vs. 14.7%) were significantly more common in the AKI group (p<0.0001). They also had greater exposure to nephrotoxic drugs (58.7% vs. 31.6%, p<0.0001) and more postpartum metabolic disturbances. AKI was associated with worse kidney outcomes: persistent dysfunction (2.4% vs. 0.1%), dialysis at discharge (1.2% vs. 0.003%), and dialysis at 30 and 90 days (0.88% vs. 0%, all p<0.0001). Neonates of AKI mothers had higher NICU admission rates (48.7% vs. 9.8%, p<0.0001). Maternal mortality was also higher (0.88% vs. 0.12%, p=0.0088). Conclusion: In this large U.S. cohort, PRAKI was strongly associated with comorbidities, hypertensive disorders, and adverse maternal and neonatal outcomes. These findings emphasize the need for early recognition and multidisciplinary management of high-risk pregnancies to reduce avoidable complications.