The Safety and Efficacy of Low-Molecular-Weight Heparin in Pregnant Women With Rheumatic Heart Disease and Valves Replacement

Background: In patients with rheumatic heart disease (RHD) and prosthetic valve replacement, the risk of thromboembolic complications is the highest during and immediately after pregnancy. Therapeutic anticoagulation during this period is crucial to minimize the risk of thromboembolic complications. The use of low-molecular-weight heparin (LMWH) remains an off-label indication. The type of anticoagulants used, dosing regimens, target anti-Xa levels, and frequency of anti-Xa monitoring are highly variable in the pregnant population and have been derived from pilots, observational studies, and empirical evidence. Herein, in a real-world setting, we sought to examine the efficacy and safety of variable anticoagulation options with a focus on LMWH in the management of RHD-related valvular disease in pregnant women. Methods: This study is a retrospective study conducted at a large university-affiliated tertiary care center (King Saud University Medical City) between January 2011 and February 2020. All pregnant women with RHD who had heart valve replacements were reviewed. Patient data were extracted for demographic information, baseline characteristics, anticoagulation type, and primary outcomes. Primary endpoints were thromboembolic events, hemorrhagic complications, and fetal outcomes. Results: A total of 744 pregnancies in 149 women were identified. The mean age ± SD of the women was 43.8 ± 12 years. A total of 86 women (58%) were on the LMWH regimen, 35 women (23%) were on LMWH and warfarin regimen, and 28 women (19%) were on unfractionated heparin (UFH) and warfarin regimen. Overall, thromboembolic events developed in five (0.7%) pregnancies. Of those, two were in the LMWH group, two were in the LMWH and warfarin group, and one was in the UFH and warfarin group. In addition, significant hemorrhagic complications occurred in five pregnancies. Of these, two occurred in the LMWH group, two in the LMWH and warfarin group, and one in the UFH and warfarin group. No adverse maternal and fetal outcomes were noted. Conclusion: This study presents the largest retrospective study of variable anticoagulation options in pregnant women with RHD and prosthetic valve replacement. LMWH is both safe and effective in preventing major thromboembolic complications compared to other forms of anticoagulation used during pregnancy.