Objectives: to describe changes in characteristics of delivery and postpartum hospitalisations with chronic heart disease from 1995 to 2006.
Design: cross-sectional study.
Setting: USA, nationwide hospital discharge data.
Population: a total of 47 882 817 delivery hospitalisations and 660 038 postpartum hospitalisations.
Methods: adjusted odds ratios describing the associations between chronic maternal heart disease and severe obstetric complications were obtained from multivariable logistic models. The contribution of chronic heart disease to severe morbidity was estimated using adjusted population-attributable fractions.
Main outcome measures: prevalence and trends in chronic heart disease, rate and risk of severe obstetric complications.
Results: in 2004-2006, about 1.4% of delivery hospitalisations were complicated with chronic heart disease. No substantial changes in the overall prevalence of chronic heart disease among hospitalisations for delivery were observed from 1995-1997 to 2004-2006. Even so, a linear increase was found for specific congenital heart disease, cardiac dysrhythmias, and cardiomyopathy and congestive heart failure (P < 0.01). During this same period the rate of postpartum hospitalisations with chronic heart disease tripled (P < 0.01). Severe complications during hospitalisations for delivery among women with chronic heart disease were more common in 2004-2006 than in 1995-1997. In 2004-2006, 64.5% of the cases of acute myocardial infarction, 57.5% of the instances of cardiac arrest/ventricular fibrillation, 27.8% of in-hospital mortality and 26.0% of the cases of adult respiratory distress syndrome were associated with hospitalisations with chronic heart disease.
Conclusions: in the USA chronic heart disease among women hospitalised during pregnancy may have increased in severity from 1995 to 2006.