Prognostic factors of rheumatic mitral stenosis during pregnancy and puerperium.

OBJECTIVE To identify characteristics associated with complications during pregnancy and puerperium in patients with rheumatic mitral stenosis. METHODS Forty-one pregnant women (forty-five pregnancies) with mitral stenosis, followed-up from 1991 to 1999 were retrospectively evaluated. PREDICTOR VARIABLES the mitral valve area (MVA), measured by echocardiogram, and functional class (FC) before pregnancy (NYHA criteria). Maternal events: progression of heart failure, need for cardiac surgery or balloon mitral valvulotomy, death, and thromboembolism. Fetal/neonatal events: abortion, fetal or neonatal death, prematurity or low birth weight (<2,500 g), and extended stay in the nursery or hospitalization in newborn ICU. RESULTS The mean +/- SD of age of the patients was 28.8+/-4.6 years. The eventful and uneventful patients were similar in age and percentage of first pregnancies. As compared with the level 1 MVA, the relative risk (RR) of maternal events was 5.5 (95% confidence interval (CI) =0.8-39.7) for level 2 MVA and 11.4 (95% CI=1.7-74.5) for level 3 MVA. The prepregnancy FC (FC > or = II and III versus I) was also associated with risk for maternal events (RR=2.7; 95% CI=1.4-5.3).MVA and FC were not importantly associated with these events, although a smaller frequency of fetal/neonatal events was observed in patients who had undergone balloon valvulotomy. CONCLUSION In pregnant women with mitral stenosis, the MVA and the FC are strongly associated with maternal complications but are not associated with fetal/neonatal events. Balloon mitral valvulotomy could have contributed to reducing the risks of fetal/neonatal events in the more symptomatic patients who had to undergo this procedure during pregnancy.