Heart valve prostheses in pregnancy: Outcomes for women and their babies

Abstract

Background: As the prognosis of women with prosthetic heart valves improves more of these individuals are contemplating and undertaking pregnancy. Accurate knowledge of perinatal outcomes is essential, assisting counselling and guiding care. The aim of this study was to assess outcomes in a contemporary population of women with heart valve prostheses undertaking pregnancy, and to compare outcomes for women with mechanical and bioprosthetic prostheses. Method and results: Longitudinally-linked population health datasets containing birth and hospital admissions data were obtained for all women giving birth in New South Wales, Australia, 2000-2011. This included information identifying presence of maternal prosthetic heart valve. Cardiovascular and birth outcomes were evaluated. Among 1 144 156 pregnancies, 136 involved women with a heart valve prosthesis (1 in 10 000). No maternal mortality was seen among these women, although the relative risk for an adverse event was higher than the general population, including severe maternal morbidity (13.9% v. 1.4%, RR=9.96, 95% CI 6.32-15.7), major maternal cardiovascular event (4.4% v. 0.1%, RR 34.6, 95% CI 14.6-81.6), preterm birth (18.3% v. 6.6%, RR=2.77, 95% CI 1.88-4.07) and small-for-gestational-age infants (19.3% v. 9.5%, RR=2.12, 95% CI 1.47-3.06). There was a trend towards increased maternal and perinatal morbidity in women with a mechanical valve compared to bioprosthetic. Conclusions: Pregnancies in women with a prosthetic heart valve demonstrate an increased risk of an adverse outcome, for both mothers and babies, compared with pregnancies in the absence of heart valve prostheses. In this contemporary population, the risk was lower than previously reported.