Pregnancy and the Risk of Aortic Dissection or Rupture: A Cohort-Crossover Analysis.

BACKGROUND Case series have described aortic dissection and rupture in pregnancy. Few population-based data exist to support an association. METHODS We performed a cohort-crossover study using data on all emergency department visits and acute care hospitalizations at nonfederal healthcare facilities in California, Florida, and New York. We included women ≥12 years of age with labor and delivery or abortive pregnancy outcome between 2005 and 2013. Our outcome was a composite of aortic dissection or rupture. Based on the timing of reported aortic complications during pregnancy, we defined the period of risk as 6 months before delivery until 3 months after delivery. We compared each patient's likelihood of aortic complications during this period with an equivalent 270-day period exactly 1 year later. Incidence rates and incidence rate ratios were computed using conditional Poisson regression with robust standard errors. RESULTS Among 6 566 826 pregnancies in 4 933 697 women, we identified 36 cases of aortic dissection or rupture during the pregnancy or postpartum period and 9 cases during the control period 1 year later. The rate of aortic complications was 5.5 (95% confidence interval, 4.0-7.8) per million patients during pregnancy and the postpartum period, in comparison with 1.4 (95% confidence interval, 0.7-2.9) per million during the equivalent period 1 year later. Pregnancy was associated with a significantly increased risk of aortic dissection or rupture (incidence rate ratio, 4.0; 95% confidence interval, 2.0-8.2) in comparison with the control period 1 year later. CONCLUSIONS The risk of aortic dissection or rupture is elevated during pregnancy and the postpartum period.