INTRODUCTION: Rheumatic heart disease (RHD) is the acquired autoimmune heart valve damage resulting from untreated infection with the Streptococcus pyogenes bacterium, which affects people experiencing socioeconomic disadvantage globally. This study measured RHD-associated major adverse cardiovascular events (MACE) and the increased risk associated with pregnancy among women diagnosed with RHD.

MATERIAL AND METHODS: Population-level analysis of all births to women with RHD in four Australian jurisdictions was conducted, which covered 71% of the total population and 88% of the Aboriginal and Torres Strait Islander population (a group who experience some of the highest RHD rates reported globally). A retrospective cohort study using linked RHD register and midwives, hospital, and death data collections was designed. Females with at least one birth record aged 12-44 years, whose first RHD diagnosis occurred prior to 20 weeks' gestation and age < 35 years, were identified during 2002-2017. Survival methods (incorporating mixed effects and time-varying covariates) estimated proportions and hazard ratios. Probability of hospitalization for new RHD-associated MACE was measured for pulmonary hypertension secondary to left heart disease, heart failure, valvular surgery, stroke, infective endocarditis, atrial fibrillation, acute pulmonary edema, cardiomyopathy, and/or death.

RESULTS: We identified 558 pregnancies in women with uncomplicated RHD (345 women) and 88 pregnancies in women with complicated RHD (60 women). During pregnancy, 4.5% of women with uncomplicated RHD and 31.8% of women with complicated RHD experienced new RHD-associated MACE. Risk of RHD-associated MACE was three- to six-fold higher during periods of pregnancy (compared with non-pregnancy) and did not differ by RHD stage.

CONCLUSIONS: After 20 weeks of gestation, women with RHD experienced RHD-associated MACE outcomes at frequencies that were contingent upon RHD stage at 20 weeks of gestation. Awareness of RHD status before 20 weeks of gestation, especially in regions where RHD is endemic, is critical for ensuring women's cardiovascular health in pregnancy and beyond.