Postpartum hemorrhage and short-term risk of cardiovascular disease

Postpartum hemorrhage is a common obstetrical complication that, in severe cases, may necessitate blood transfusion. We hypothesized that severe postpartum hemorrhage, defined as postpartum hemorrhage requiring transfusion, constitutes a cardiovascular insult that confers risk beyond the immediate postpartum period. Severe postpartum hemorrhage may plausibly be linked to cardiovascular disease by large-volume acute blood loss, causing hypoperfusion and ischemia, leading to impaired cardiac function. We additionally aimed to examine the impact of preeclampsia co-occurring with postpartum hemorrhage, as preeclampsia is strongly associated with new-onset postpartum cardiovascular disease and is also an independent risk factor for postpartum hemorrhage.

Using the Healthcare Cost and Utilization Project's Nationwide Readmissions Database, we designed a retrospective cohort study of delivery hospitalization discharges in the United States, 2010 to 2020. International Classification of Diseases 9 and International Classification of Diseases 10 codes were used to identify deliveries complicated by postpartum hemorrhage, with and without blood transfusion. Associations between postpartum hemorrhage and cardiovascular disease-related hospital readmissions and mortality within the calendar year of delivery were derived from a Cox proportional hazards model, expressed as the confounder-adjusted hazard ratio with a 95% confidence interval. Additional analysis was performed of the associations between postpartum hemorrhage and cardiovascular disease events stratified by patients who were normotensive and those with preeclampsia.

Of the 38,311,537 delivery hospitalizations, 3.9% (n=1,501,235) were complicated by postpartum hemorrhage. Of these, 13.3% (n=199,810) received a blood transfusion. Compared to patients without postpartum hemorrhage, patients with postpartum hemorrhage without transfusion had a similar risk of overall cardiovascular disease mortality and heart disease mortality, and a similar risk of nonfatal cardiovascular disease readmission. Patients with postpartum hemorrhage with transfusion had about a 2.6-fold increased risk of overall and heart disease-related cardiovascular disease mortality and a 67% increased risk of cardiovascular disease readmission compared to patients without postpartum hemorrhage. When exposures were stratified by preeclampsia status, the risk of cardiovascular disease readmission for postpartum hemorrhage without transfusion was similar to the risk with no postpartum hemorrhage for both normotensive and preeclampsia patients. The risk of cardiovascular disease readmission for postpartum hemorrhage with transfusion versus no postpartum hemorrhage was elevated two-fold in normotensive patients and by 36% in patients with preeclampsia.

Severe postpartum hemorrhage is associated with an increased risk of cardiovascular disease readmission and mortality within the calendar year of delivery. The highest risk for cardiovascular disease events was observed in patients with co-occurring preeclampsia. These findings underscore the burden of cardiovascular disease risk associated with severe postpartum hemorrhage and highlight the need for additional research to identify interventions that can mitigate the risk of adverse cardiovascular outcomes.