title: Anti-coagulation during pregnancy in women with mechanical heart valves: a prospective study.
abstract: BACKGROUND
  Pregnancy is associated with a hypercoagulable state, therefore the optimal anticoagulants for potential use in pregnant women with prosthetic heart valves are controversial. The aim of this study is to investigate the effect of anticoagulants on pregnancy outcomes and their potential risks in pregnant women with mechanical heart valves.
  
  
  METHODS
  In this prospective cohort study, we followed 44 women with 49 pregnancies who had mechanical heart valves from September 2002 to September 2007. A total of 38 patients took warfarin throughout their pregnancies (group A). In 11 patients, warfarin was changed to heparin during the first trimester and then again to warfarin during 12thto 36thweeks of gestational age (group B). All women took warfarin from 36thweeks of gestational age until delivery.
  
  
  RESULTS
  In group A, there were 22 live births (57.9%), 15 abortions (39.5%) and 1 maternal death (2.6%). In group B, there were seven live births (63.6%), three spontaneous abortions (27.3%) and one intra-uterine fetal death (9.1%). There was no significant difference in live birth rate between the two groups (p=0.24). Thirty-three pregnancies (86.8%) in group A and five pregnancies (45.4%) in group B had no maternal complications (p=0.004). The difference in pregnancy complications between both groups was significant (p<0.001).
  
  
  CONCLUSIONS
  The present study shows that low dose warfarin (5 mg/day or less) may be safe during the first trimester of pregnancy. Maternal adverse events are low when pregnant women with mechanical heart valves remain on a warfarin regimen. The risk of embryopathy does not necessarily increase.
authors.affiliation: Heart Valve Research Center, Shaheed Rajaei Cardiovascular Medical and Research Center, Tehran University of Medical Science, Tehran, Iran.
authors.forename: Amir Jamshid
authors.initials: AJ
authors.lastname: Khamoushi
authors.affiliation: Heart Valve Research Center, Shaheed Rajaei Cardiovascular Medical and Research Center, Tehran University of Medical Science, Tehran, Iran ; Epidemiology and Reproductive Health Department, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran.
authors.forename: Fahimeh
authors.initials: F
authors.lastname: Kashfi
authors.affiliation: Heart Valve Research Center, Shaheed Rajaei Cardiovascular Medical and Research Center, Tehran University of Medical Science, Tehran, Iran.
authors.forename: Saeid
authors.initials: S
authors.lastname: Hosseini
authors.affiliation: Heart Valve Research Center, Shaheed Rajaei Cardiovascular Medical and Research Center, Tehran University of Medical Science, Tehran, Iran.
authors.forename: Ali Reza
authors.initials: AR
authors.lastname: Alizadeh Ghavidel
authors.affiliation: Heart Valve Research Center, Shaheed Rajaei Cardiovascular Medical and Research Center, Tehran University of Medical Science, Tehran, Iran.
authors.forename: Niloufar
authors.initials: N
authors.lastname: Samiei
authors.affiliation: Cardiac Surgery Department, Afshar Hospital, Yazd, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Haddadzadeh
keywords: Anticoagulant; Heparin; Mechanical Heart Valve; Pregnancy; Warfarin