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Low-dose warfarin maternal anticoagulation and fetal warfarin syndrome
  1. Ana R Sousa1,2,
  2. Rita Barreira3,
  3. Edmundo Santos2
  1. 1Department of Pediatric Cardiology, Centro Hospitalar de Lisboa Ocidental EPE, Lisbon, Portugal
  2. 2Department of Neonatology, Centro Hospitalar de Lisboa Ocidental EPE, Lisbon, Portugal
  3. 3Department of Pediatrics, Centro Hospitalar de Lisboa Ocidental EPE, Lisbon, Portugal
  1. Correspondence to Dr Ana R Sousa, asousa{at}


Fetuses exposed to warfarin during pregnancy are at an increased risk of developing an embryopathy known as fetal warfarin syndrome or warfarin embryopathy. The most consistent anomalies are nasal hypoplasia and stippling of vertebrae or bony epiphyses. Management of pregnant patients on anticoagulation is challenging. Current guidelines suggest the use of warfarin if the therapeutic dose is ≤5 mg/day. We report the case of a newborn with signs of warfarin embryopathy born from a mother anticoagulated with warfarin due to mechanical mitral and aortic heart valves. Warfarin was required at the dose of 5 mg/day and was withheld without medical advice between weeks 8 and 10 with no other anticoagulation. The newborn presented with skeletal abnormalities and a ventricular septal defect that have not required specific treatment during the first year of life. Low-dose warfarin is associated with a lower risk of warfarin-related fetopathy but the risk of embryopathy seems unchanged.

  • valvar diseases
  • paediatrics (drugs and medicines)
  • warfarin therapy
  • drugs: obstetrics and gynaecology
  • unwanted effects / adverse reactions

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  • Contributors All authors contributed to the conception of the work and to the acquisition and analysis of data for the work. ARS and RB were responsible for drafting and ES critically revised the work. All authors approved the final version to be published and are accountable for all aspects of the work and for ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.