Characteristics and outcomes of AKI treated with dialysis during pregnancy and the postpartum period

Acute kidney injury 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 to study all consecutive pregnancies over a 15-year period (1997 to 2011) in Ontario, Canada and describe the incidence and outcomes of acute kidney injury treated with dialysis during pregnancy or within 12 weeks of delivery. Of 1,918,789 pregnancies over 15 years, 188 were complicated by acute kidney injury treated with dialysis (incidence: 1 per 10,000 [95% confidence interval 0.8 to 1.1]). Only 21 of 188 (11.2%) had record of a preexisting medical condition; however, 130 (69.2%) experienced a major pregnancy-related complication including preeclampsia, thrombotic microangiopathy, heart failure, sepsis, and postpartum hemorrhage. Eight women died (4.3% vs. 0.01% in the general population), and 7 (3.9%) 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% vs. 14.0%; relative risk 3.40, 95% confidence interval 2.52 to 4.58). There were no stillbirths and fewer than 5 neonatal deaths (< 2.7%) in affected pregnancies compared with 0.1% and 0.8% in the general population, respectively. Acute kidney injury 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.