May 19 2022

Classification of the active ingredient acenocoumarol

Risk level in pregnancy: This medicine is classified as Category D for women with mechanical heart valves; Category X for other pregnant.

Acenocoumarol passes through the placenta and there is fetal risk of hemorrhage, even if the mother INR is maintained within the therapeutic range. There have been observations of malformations in children whose mothers were treated with coumarin derivatives, group that owns this medicine. These abnormalities include nasal hypoplasia and stippled epiphyses (chondrodysplasia punctata) in the fetus, among other malformations. When taken late in pregnancy may cause optic atrophy and microcephaly. The incidence of coumarin anticoagulants embryopathy is greater than 6%.

So acenocoumarol should not be used during pregnancy, being necessary to use effective contraception during treatment with this drug to prevent pregnancy.

Update 10.12.2010

Meaning of category X

Studies in animals or humans have demonstrated fetal abnormalities and/or there is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience, and the risks involved in use of the drug in pregnant women clearly outweigh potential benefits.