Anticoagulant therapy in pregnant women with mechanical and bioprosthetic heart valves.

Objective: The aim of the present study was to review maternal and fetal outcomes in pregnant women with prosthetic heart valves.

Methods: A retrospective record review of pregnant women with prosthetic heart valves on anticoagulation was performed at the Specialist Cardiac Antenatal Clinic, Johannesburg South Africa from 2015 to 2023.

Results: Fifty pregnancies with mechanical heart valves and three with tissue valves, on anticoagulation for comorbid atrial fibrillation were identified. The majority were of African ethnicity at a mean age of 33 ± 6 years. Anti-Xa adjusted enoxaparin was commenced at 10.5 ± 5.6 weeks' gestation until delivery in 48 (90.6%) pregnancies and warfarin was continued in five (9.4%) pregnancies. The live birth rates on enoxaparin and warfarin were 56.3% (95% confidence interval [CI]: 42.3-69.3) and 20.0% (95% CI: 2.0-64.0), respectively. There were 12 (22.6%) miscarriages at a mean of 11.3 ± 3.7 weeks' gestation, four (7.5%) intrauterine fetal deaths on warfarin and two (3.8%) warfarin embryopathy/fetopathy. The rates of antepartum/secondary postpartum bleeding and primary postpartum bleeding were 29.4% (95% CI: 18.6-43.1) and 5.9% (95% CI: 1.4-16.9), respectively. Maternal complications included anemia (n = 11, 20.8%), arrhythmia (n = 2, 3.8%), heart failure (n = 2, 3.8%) and paravalvular leak (n = 2, 3.8%). There was one (1.9%) mitral valve thrombosis and one (1.9%) stuck valve in pregnancies who defaulted warfarin prior to pregnancy. There were no maternal deaths.

Conclusion: Multidisciplinary management of pregnant women with prosthetic heart valves with anti-Xa adjusted low molecular weight heparin throughout pregnancy represents an effective anticoagulation option for low-middle-income countries.