Prosthetic heart valves in pregnancy, outcomes for women and their babies: a systematic review and meta‐analysis

Background Historically, pregnancies among women with prosthetic heart valves have been associated with an increased incidence of adverse outcomes. Objectives Systematic review to assess risk of adverse pregnancy outcomes among women with a prosthetic heart valve(s) over the last 20 years. Search strategy Electronic literature search of Medline, The Cochrane Library, Cumulative Index to Nursing and Allied Health Literature and Embase to find recent studies. Selection criteria Studies of pregnant women with heart valve prostheses including trials, cohort studies and unselected case series. Data collection and analysis Primary analysis calculated absolute risks and 95% confidence intervals (CI) for pregnancy outcomes using a random effects model. The Freeman–Tukey transformation was utilised in secondary analysis due to the large number of individual study outcomes with zero events. Main results Eleven studies capturing 499 pregnancies among women with heart valve prostheses, including 256 mechanical and 59 bioprosthetic, were eligible for inclusion. Pooled estimate of maternal mortality was 1.2/100 pregnancies (95% CI 0.5–2.2), for mechanical valves subgroup 1.8/100 (95% CI 0.5–3.7) and bioprosthetic subgroup 0.7/100 (95% CI 0.1–4.5), overall pregnancy loss 20.8/100 pregnancies (95% CI 9.5–35.1), perinatal mortality 5.0/100 births (95%CI 1.8–9.8) and thromboembolism 9.3/100 pregnancies (95% CI 4.0–16.5). Conclusions Women with heart valve prostheses experienced higher rates of adverse outcomes than expected in a general obstetric population; however, lower than previously reported. Women with bioprostheses had significantly fewer thromboembolic events compared to women with mechanical valves. Women should be counselled pre‐pregnancy about risk of maternal death and pregnancy loss. Vigilant surveillance by a multidisciplinary team throughout the perinatal period remains warranted for these women and their infants. Tweetable Metaanalysis suggests improvement in #pregnancy outcomes among women with #heartvalveprostheses.