I read with great interest the article, Factor V Leiden carriers taking oral contraceptives have an increased risk of thrombosis, published in the Journal this January, in which the authors discuss the risk of cardiovascular events in women taking combined oral contraceptives. In effect, the use of oral contraceptives (OCs) has been associated with an increased risk of thrombosis.

In the aforementioned Journal article, the authors report some clinical circumstances that may increase this risk, among which they cite smoking in women 35 years old or older and women with a history of ischemic heart disease or stroke, hypertension, diabetes, and dyslipidemia.

It strikes us that among these risk factors the authors do not cite carriers of factor V Leiden because it is known that the presence of this thrombotic risk factor may increase the possibility of thrombotic events in women taking contraceptives.

Moreover, the prevalence of factor V Leiden in the European population is about 5%, ranging from 0.6% to 13.0%, and the prevalence of factor V Leiden carriers among white patients with deep venous thrombosis varies between 11.2% and 37.0%, so the possibility of overlap between female factor V Leiden carriers and the intake of contraceptives could be common.

For this reason, we have raised the question of whether it would be reasonable to perform screening for factor V Leiden before oral contraception. One of the arguments against screening for factor V Leiden to prevent secondary thrombotic events in women taking OCs is the economic cost. We evaluated this and concluded that screening for factor V Leiden may be recommended in women who are going to begin OC treatment if they have had previous thrombotic events or a family history of thrombosis.