Prosthetic heart valves raise pregnancy risks: the complications may be preventable and suggest a need for specialized care and close monitoring.
Maternal complications were primarily thromboembolic events and hemorrhages. Embryopathy was usually caused by oral anticoagulant use during the first trimester, whereas anticoagulant use during the second and third trimesters was associated with a high fetal loss rate.
"These complications may be preventable and suggest a need for specialized care and close monitoring of pregnancies in women with a prosthetic heart valve," said Dr. Citania L. Tedoldi and her associates in a poster at the annual scientific sessions of the American Heart Association.
The researchers reviewed the pregnancy outcomes of women with prosthetic heart valves who delivered at any of three tertiary centers in Brazil during January 1995-December 2004. The mean age of the mothers was 26 years.
In 69 pregnancies, the mothers received anticoagulant therapy in the first trimester. Of those, 47 received an oral anticoagulant and 22 were treated with heparin. Anti-coagulants were used on 65 women during the second trimester (61 on an oral agent and 4 on heparin), and 60 received an anticoagulant during the third trimester (57 on an oral agent and 3 on heparin).
During pregnancy or delivery, 2 women died, 9 had a major thromboembolism, and 15 developed a major bleed. The two deaths were both caused by thrombosis of prosthetic mitral valves triggered by inadequate anticoagulation with heparin. All of the thromboembolic events were in women with mitral valve prostheses; no events occurred in women with atrial fibrillation. Of the 15 major bleeds, 11 were caused either by insufficient hemostatic procedures during surgery or by incomplete uterine evacuation, said Dr. Tedoldi, a cardiologist at Hospital Nossa Sonhora da Conceicao in Porto Alegre, Brazil.
The risk of thromboembolism was increased 10-fold in women with inadequate anticoagulation, compared with those with adequate anticoagulation.
Other factors associated with relatively small increases in the risk of thromboembolism were high-risk pregnancies, which increased the risk by 35%, having more than one prosthetic valve, which raised the risk by 35%, and a history of thromboembolism, which raised the risk by 20%, but none of these differences was statistically significant. Of the 15 major bleeds, 4 were judged unavoidable. The six bleeds caused by insufficient hemostasis during surgery and the five caused by incomplete uterine evacuation were judged preventable.
The 86 pregnancies resulted in 63 live births, with a mean gestational age of 36 weeks at delivery. Average birth weight was 2,636 g. Cesarean section was used for 40 of 70 deliveries.
There were eight fetal deaths (9%), higher than the expected 3% rate. Neonatal deaths occurred in 4 of the 63 live births (6%), higher than the expected 1% rate. Embryopathy occurred in 2 of the 47 pregnancies exposed to warfarin during the first trimester. The cohort showed no significant increase above expected levels for spontaneous abortions, malformations, or prematurity.
BY MITCHEL L. ZOLER
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|Title Annotation:||Clinical Rounds|
|Author:||Zoler, Mitchel L.|
|Publication:||OB GYN News|
|Date:||Mar 1, 2006|
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