Anticoagulation in Patients with Mechanical Valves during Pregnancy

Abstract

Mechanical valve thrombosis is a life-threatening event, while pregnancy is associated with a hypercoagulable state. Thus, in pregnant women with mechanical valves, adequate anticoagulation becomes even more critical. This prospective study was conducted to establish a uniform anticoagulation regimen for these women. A total of 250 pregnancies in 245 women with mechanical heart valves were evaluated. The patients were divided into 2 groups: group 1 (n = 150) took oral warfarin throughout pregnancy and group 2 (n = 100) received subcutaneous heparin in the 1(st) trimester and oral warfarin for the other trimesters. Both groups received heparin at the time of delivery. There were no coumarin-induced fetal malformations. Minor thromboembolic episodes took place in 5 women in group 1 and 3 in group 2. Valve thrombosis occurred in 1 woman in group 2 and led to 1 maternal death in this series. The incidence of spontaneous abortion was similar between the groups. We conclude that warfarin is safe and convenient to use during pregnancy. The teratogenic effects of warfarin during the 1(st) trimester are overstated, and switching to heparin is not mandatory.

Mechanical Aortic Valve Replacement in Young Women Planning on Pregnancy

“…Nevertheless, both because available data in literature are few and somewhat contradictory and because inclusion criteria and management protocol of the present study were stringent, even the analysis of a small series may add importantly to the knowledge of the topic. Second, dose dependency of warfarin fetal complications was originally suggested by our group and later supported by reports from others (23,24) published in lower visibility journals. Overall, the evidence of the safety of low-dose warfarin is currently based on low numbers: the present study itself, as none of the patients requiring Ͼ5 mg warfarin daily chose to become pregnant on warfarin, could not provide any further support to that theory.…”

Clinical outcomes of pregnant women with mechanical heart valves

“…Gelanie ve ark. [9] 245 hastada 250 gebelik takip etmiş ve bir gruba gebelik boyunca varfarin verirken diğer grupta ilk trimesterde subkutan heparine dönmüşler, fetal embriyopati gözlemezken, heparin grubunda kapak trombozuna bağlı maternal ölüm bildirmişlerdir. Benzer şekilde Akhtar ve ark., [1] gebelikte varfarinin efektif olduğu sonucuna varmışlar ve tüm gebelik boyunca, doğuma yaklaşana kadar, varfarin kullanımını önermiş-lerdir.…”

Fetal warfarin syndrome

“…While some authors report that the incidence of fetal warfarin syndrome has been hitherto overestimated, they are in the overwhelming minority 9. Warfarin provides the greatest thromboprophylactic benefit to mothers but is associated with appreciable rates of fetal wastage and congenital malformations.…”