Abstract Number: PB1303
Meeting: ISTH 2021 Congress
Background: Anticoagulation of pregnant woman with mechanical prosthetic heart valves is associated with significant maternal and fetal risks. In order to reduce the risks of embryopathy associated with first trimester vitamin K antagonists such as warfarin, sequential therapy with dose adjusted therapeutic low molecular weight heparin and warfarin has been recommended. Nonetheless, this does not obviate the risks of central nervous system (CNS) abnormalities, miscarriages and stillbirths, which have been described following warfarin exposure during any trimester.
Aims: To describe the CNS abnormalities of a fetus of a pregnant woman with a mechanical valve replacement on lifelong warfarin therapy.
Methods: A 30-year-old African female, presented at 11 weeks’ gestation. She was receiving warfarin (Aspen Pharmacare) 7.5 mg daily for a second generation mechanical mitral valve replacement for rheumatic heart disease. This was associated with a time in therapeutic range of 88.8 %. Past obstetric history included recurrent first trimester and one second trimester miscarriages associated with anticoagulation. On presentation, the international normalized ratio (INR) was 6.78 with no associated signs of bleeding. A termination of pregnancy was performed. Written informed consent was obtained and the research was approved by the institutional Ethics Committee (M-200547).
Results: Post-mortem examination of the male fetus showed a small flattened skull. No cerebellar or cerebral tissue was present in the skull confirming anencephaly (Figure 1).
Conclusions: The findings of this case report, add to the few previously described cases of anencephaly and a meningocele. These CNS abnormalities are caused by intrauterine hemorrhage. In order to improve fetal outcomes, a multidisciplinary approach in pregnant women with mechanical prosthetic heart valves is essential. This includes contraception advice at anticoagulation clinics, pre-pregnancy planning and early presentation or replacement of warfarin with heparin prior to conception.
To cite this abstract in AMA style:Monaheng R, Schapkaitz E, Rhemtula H, Louw M, AG. Warfarin Anticoagulation and Fetal Central Nervous System Abnormalities: A Case Report [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/warfarin-anticoagulation-and-fetal-central-nervous-system-abnormalities-a-case-report/. Accessed February 20, 2024.
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