Pregnancy outcomes in women with mechanical heart valves

To evaluate maternal complications and perinatal outcomes in women with mechanical heart valves treated with warfarin and heparin during pregnancy.

A retrospective chart review was performed on 45 pregnancies in 28 women who were previously fitted with mechanical valve prostheses and treated between 1991 and 2005 at Seoul National University Hospital. Outcome parameters were maternal complications and perinatal outcomes.

Overall, there were 27 live births (60%), 7 stillbirths (15.6%), 2 therapeutic terminations in the second trimester (4.4%), 9 first-trimester spontaneous abortions (20%) and 2 neonatal deaths after preterm delivery. After excluding 9 first-trimester spontaneous abortions and 3 pregnancies administered warfarin throughout pregnancy, there were significantly more live births among patients administered heparin only after a diagnosis of pregnancy than among those administered warfarin from the second trimester (11 of 11 vs. 13 of 22, p = 0.015). One patient with mitral valve thrombosis during heparinization in the first trimester received valve replacement surgery and then aborted. Late postpartum hemorrhage occurred in 1 patient. All stillbirths and therapeutic terminations occurred in women being administered warfarin.

Warfarin use from the second trimester in combination anticoagulation regimens increases the risk of an adverse perinatal outcome.