Prosthetic Heart Valves and Pregnancy

Abstract

In patients with prosthetic heart valves (PHV), pregnancy is associated with the risks of warfarin embryopathy in patients with mechanical PHV and of structural valve deterioration (SVD), both early and late, in patients with biological PHV. ### Warfarin The use of warfarin, particularly between the 6th and 12th weeks of pregnancy, is associated with an embryopathy, “warfarin embryopathy,”1,2 which is characterized by nasal hypoplasia and/or stippled epiphyses.3 Uncommon features, including central nervous system and eye abnormalities, may be due to warfarin exposure during the second and third trimester.3 There is a wide range of the reported incidence of warfarin embryopathy (Table 1).3–18 Ten studies comprising 427 pregnancies reported the incidence was zero (Table 1). From the patient’s point of view, the incidence per live birth may be more important; four recent (between 1994 and 99) studies reported an incidence of 3/189 (1.6%) live births7,9,17,18 (Table 1). One group has shown that the risk of warfarin embryopathy was extremely low in the 33 women who needed ≤5 mg of warfarin to maintain an adequate INR.14,18 View this table: TABLE 1. Incidence of Warfarin Embryopathy The incidence of warfarin embryopathy will be lower with use of IV unfractionated heparin in the first 3 months (especially between the 6th to 12th weeks) of pregnancy; one review concluded that this strategy “eliminated the risk.”19 IV unfractionated heparin use in the last 2 weeks of pregnancy is associated with a reduced risk of hemorrhage during delivery and the neonatal period in the mother, as well as in the baby, because warfarin crosses the placenta, and therefore, the fetus/baby is anticoagulated. To reduce the latter complication, some have suggested elective caesarian section in the 38th week of pregnancy.17,18 An earlier study reported the incidence of abortion and stillbirths in these patients was …