 Women who are planning to use oral contraceptives do not benefit from routine screening for thrombophilias , as the absolute risk of thrombotic events is low . If either the woman or a first @-@ degree relative has suffered from thrombosis , the risk of developing thrombosis is increased . Screening this selected group may be beneficial , but even when negative may still indicate residual risk . Professional guidelines therefore suggest that alternative forms of contraception be used rather than relying on screening . 
