Erroneous Clinical Diagnosis of Leg Vein Thrombosis in Women on Oral Contraceptives

Abstract

Most studies demonstrating an increased risk of venous thromboembolism in women on oral contraceptives are based on clinical manifestations of the disease. Due to the fallibility of the clinical diagnosis of suspected leg vein thrombosis, Doppler ultrasonic evaluation (with a 93% accuracy compared to venography) was performed for clinical manifestations in deep vein thrombosis in 54 women taking birth control pills and 75 women of similar age who were not on contraceptives. Clinical diagnosis was confirmed by Doppler in only 16.7% of women taking contraceptives and 30.7% of women not taking contraceptives (P = 0.052). Apparently the clinical diagnosis of leg vein thrombosis is frequently erroneous, particularly in women taking oral contraceptives. Future investigations reporting venous thromboembolism associated with oral contraceptives should be based on diagnoses validated by accurate objective techniques.