Clear and present danger: Mechanical heart valves in pregnancy.

Specialists in Obstetric Haematology continue to be challenged by pregnant women with mechanical heart valves, who are at high risk of death or severe morbidity. Effective anticoagulation to reduce valve thrombosis inevitably increases risk of obstetric haemorrhage and fetal loss or harm, and difficult decisions need to be made. Lester and mulitdisciplinary colleagues on behalf of the British Society for Haematology review available evidence and provide comprehensive recommendations to guide management in this difficult area. Commentary on: Lester et al. British Society for Haematology guideline for anticoagulant management of pregnant individuals with mechanical heart valves. Br J Haematol 2023;202:465-478.