Characteristics and Outcomes of AKI Treated with Dialysis during Pregnancy and the Postpartum Period

Acute kidney injury (AKI) is a rare complication of pregnancy, but may be associated with significant morbidity and mortality in young and often otherwise healthy women. We conducted a retrospective population-based cohort study of all consecutive pregnancies over a 15-year period (1997-2011) in Ontario, Canada, and describe the incidence and outcomes of AKI treated with dialysis during pregnancy or within 12 weeks of delivery. Of 1,918,789 pregnancies, 188 were complicated by AKI treated with dialysis (incidence: 1 per 10,000 [95% confidence interval, 0.8 to 1.1]). Only 21 of 188 (11.2%) women had record of a preexisting medical condition; however, 130 (69.2%) women experienced a major pregnancy-related complication, including preeclampsia, thrombotic microangiopathy, heart failure, sepsis, or postpartum hemorrhage. Eight women died (4.3% versus 0.01% in the general population), and seven (3.9%) women remained dialysis dependent 4 months after delivery. Low birth weight (<2500 g), small for gestational age, or preterm birth (<37 weeks' gestation) were more common in pregnancies in which dialysis was initiated (35.6% versus 14.0%; relative risk, 3.40; 95% confidence interval, 2.52 to 4.58). There were no stillbirths and fewer than five neonatal deaths (<2.7%) in affected pregnancies compared with 0.1% and 0.8%, respectively, in the general population. In conclusion, AKI treated with dialysis during pregnancy is rare and typically occurs in healthy women who acquire a major pregnancy-related medical condition such as preeclampsia. Many affected women and their babies have good short-term outcomes.