Abstract
Mechanical heart valves carry significant risk during pregnancy. Aim: To assess the risk of pregnancy and delivery for mother and child in women with mechanical heart valve prosthesis.
Methods: Multicenter retrospective observational study of women with mechanical heart valve prosthesis. The regimen with low molecular weight heparin throughout pregnancy (LMWH) was compared to warfarin since the second trimester (W).
Results: Out of 419 pregnant women with cardiovascular diseases we assessed 14 women with mechanical heart valve prosthesis (3.3%) who experienced 23 pregnancies. There were 13 pregnancies with aortic valve prosthesis, 8 with prosthesis of atrio-ventricular valves and 2 pregnancies with both aortic and mitral valve prosthesis.
LMWH regimen was used in 18 pregnancies, W in 5 pregnancies. Major maternal complications occurred in 65% of pregnancies, including 3 strokes and 3 urgent cardio-surgical procedures, all in women with LMWH regimen.
Prosthetic valve thrombosis occurred in 26%, all in the LMWH group; no thrombosis was found in W group, (p=0.166). Major bleeding occurred in 30% with no difference between LMWH and W groups (p=0.596).
Fetal loss represented 26% of all pregnancies with no difference between LMWH and W group (p=1). The birth weight was not significantly different between LMWH and W groups (2496+-327 g vs. 3132+-592 g, p=0.12).
Conclusion: The rate of maternal and fetal complications in pregnant women with mechanical valve prosthesis is still high. The anticoagulation regimen using warfarin since the second trimester appears to be the safest one.
The best prevention of complications is to avoid the implantation of mechanical valve prosthesis in girls and women in fertile age.