Infection During Delivery Hospitalization and Risk of Readmission for Postpartum Stroke

Background and Purpose- Most cases of pregnancy-related ischemic stroke (IS) and hemorrhagic stroke (HS) occur postpartum. Infections have been identified as a trigger for strokes in young people and have been associated with strokes during delivery hospitalizations, but a temporal relationship has been difficult to establish. We hypothesized that infections diagnosed during a delivery admission would be associated with an increased risk of readmission for postpartum stroke. Methods- We conducted a retrospective cohort study using the Healthcare Cost and Utilization Project's National Readmissions Database from 2010 to 2014. Using weighted survey design Poisson regression analysis, we calculated adjusted risk ratios (aRR) and 95% CI for the association between infection during delivery admission and 30-day postpartum readmission for IS or HS. Results- Out of 17.2 million delivery admissions during the study period, 2128 were readmitted within 30 days for a stroke of any type. There were 1189 HS (intracerebral hemorrhage or subarachnoid hemorrhage) and 720 IS, and the remainder unspecified pregnancy-related stroke. Adjusting for age and comorbidities, women with delivery infections were at higher risk of readmission for postpartum stroke of any type (aRR, 1.19; 95% CI, 1.01-1.41). Women with infections had higher risk of readmission for postpartum IS (aRR, 1.75; 95% CI, 1.37-2.22), but not for postpartum HS (aRR, 0.96; 95% CI, 0.75-1.23). The effect of infection on 30-day IS readmission was larger in women without hypertensive disorders of pregnancy (aRR, 2.0; 95% CI, 1.55-2.69 in women without hypertensive disorders of pregnancy versus aRR, 1.47; 95% CI, 0.9-2.38 in women with hypertensive disorders of pregnancy, P value for interaction=0.09). Conclusions- Infection during delivery hospitalization was associated with increased risk of readmission for IS, but not HS, within 30 days postpartum, particularly in women without hypertensive disorders of pregnancy. Infection may play a role in triggering postpartum IS even in the absence of other risk factors.