Intervention for Women With Native VHD Before and During Pregnancy 13.1.2.1. Pre-Pregnancy Intervention Recommendations for Pre-Pregnancy Intervention in Women With VHD Referenced studies that support the recommendations are summarized in Online Data Supplement 43. COR LOE Recommendations In symptomatic women with severe VHD who are considering pregnancy, intervention before pregnancy is recommended on the basis of CLINICAL STATEMENTS AND GUIDELINES In women who require a valve intervention before pregnancy, 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. In asymptomatic women with severe rheumatic MS (mitral valve area 1.5 cm2 , Stage C1) who are considering pregnancy, PMBC at a Comprehensive Valve Center is reasonable before pregnancy for those who have favorable valve morphology.1 5,12,13 In women of childbearing age who require valve replacement, bioprosthetic valves are preferred over mechanical valves because of the increased maternal and fetal risks of mechanical heart valves in pregnancy.14 In asymptomatic women with severe AS (aortic velocity 4.0 m/s or mean pressure gradient 40 mmHg, Stage C) who are considering pregnancy, valve intervention before pregnancy is reasonable. In asymptomatic women with severe AS (aortic velocity 4.0 m/s or mean pressure gradient 40 mmHg, Stage C1) who are considering pregnancy, do not meet COR 1 criteria for intervention, and have a preconception evaluation confirming the absence of symptoms (including normal exercise stress testing and serum BNP measurements), medical management during pregnancy may be considered to avoid prosthetic valve replacement. 