Similarly, the advice for those with hereditary thrombophilia such as the Factor V Leiden and Prothrombin gene mutations, is to consider HRT containing transdermal estradiol as this is unlikely to increase the risk of VTE/ATE above background risk.5,9 Whilst testing for thrombophilia is only advised on a selective basis in those with risk factors such as family history, a positive result would trigger a consultation with a haematologist and the advice is that HRT containing transdermal estradiol is unlikely to increase their VTE risk above their own background risk.3 This evidence concerns the gene F2 and Rare hereditary thrombophilia.