From the Guidelines
Bioprosthetic valves are preferred over mechanical valves for women who are pregnant or planning pregnancy due to the increased maternal and fetal risks associated with mechanical heart valves in pregnancy. This recommendation is based on the most recent guidelines, including the 2020 ACC/AHA guideline for the management of patients with valvular heart disease 1, which suggests that bioprosthetic valves are preferred over mechanical valves in women of childbearing age who require valve replacement. The main concern with mechanical valves is the need for lifelong anticoagulation therapy with warfarin, which can cause fetal hemorrhage, embryopathy, and pregnancy loss 1.
Key Considerations
- Bioprosthetic valves do not require long-term anticoagulation, making them safer during pregnancy, unless there are other indications for anticoagulation.
- Bioprosthetic valves have limited durability, typically 10-15 years, and may deteriorate more rapidly in younger patients, potentially necessitating reoperation.
- The decision between valve types should be individualized, considering the woman's age, future pregnancy plans, ability to manage anticoagulation, and preferences regarding reoperation risk versus anticoagulation complications.
Management of Existing Mechanical Valves
If a mechanical valve is already in place when pregnancy occurs, anticoagulation management becomes complex, with options including continuing warfarin throughout pregnancy, switching to low-molecular-weight heparin or unfractionated heparin during the first trimester, or using heparin throughout pregnancy 1. The choice of anticoagulation strategy should be based on a careful assessment of the risks and benefits for both the mother and the fetus.
Shared Decision-Making
The choice of prosthetic valve should be based on a shared decision-making process that accounts for the patient’s values and preferences, including discussion of the risks of mechanical valves during pregnancy and the reduced durability of bioprosthetic valves in young women 1. This approach ensures that women are fully informed and able to make decisions that align with their individual circumstances and priorities.
From the Research
Comparison of Mechanical and Bioprosthetic Valves in Pregnancy
- The choice between mechanical and bioprosthetic valve replacement in women of childbearing age is a complex one, with both options carrying unique risks and benefits 2, 3.
- Mechanical valves require anticoagulation therapy, which can increase the risk of maternal and fetal complications, such as bleeding and birth defects 2, 3.
- Bioprosthetic valves, on the other hand, may degenerate more quickly in young women, particularly those who become pregnant, which can lead to the need for reoperation 3, 4.
- However, some studies suggest that bioprosthetic valves may be a better option for women of childbearing age, as they avoid the need for anticoagulation therapy and may have a lower risk of maternal and fetal complications 3, 4.
- A retrospective analysis of 103 women who underwent valve replacement found that those with bioprosthetic valves had a lower incidence of miscarriages and therapeutic abortions compared to those with mechanical valves 3.
- Another study found that pregnancy did not accelerate structural degeneration in bioprostheses, and that the probability of freedom from clinical events was higher in women who became pregnant after bioprosthesis replacement 4.
Risks and Complications
- Both mechanical and bioprosthetic valves carry risks and complications during pregnancy, including maternal and fetal mortality, bleeding, and birth defects 2, 3, 5.
- Anticoagulation therapy required for mechanical valves can increase the risk of bleeding and other complications, while bioprosthetic valves may degenerate more quickly in young women 2, 3.
- Transcatheter valve replacement may be a safer and effective alternative to surgical replacement for women with severe bioprosthetic valve stenosis during pregnancy 6.
Management and Counseling
- Preconception counseling and assessment are recommended for women with prosthetic heart valves, and care should be delivered throughout pregnancy in a specialized program for high-risk patients by a multidisciplinary team 5.
- Women with prosthetic heart valves should be closely monitored during pregnancy, and anticoagulation therapy should be carefully managed to minimize the risk of complications 2, 3.