Hormonal Contraceptive Use After Venous Thrombosis: Practice From 1999 to 2004

Background: Current guidelines state that women using combined hormonal contraceptives should stop using these preparations after a venous thrombosis. The aim of this study was to assess to what extent these guidelines are followed in daily practice. Methods: Women younger than 50 years with a hormonal contraceptive-associated venous thrombosis were selected from the Multiple Environmental and Genetic Assessment of risk factors for venous thrombosis (MEGA) study. Data on hormonal contraceptive use after the event and advice from a physician were collected at venepuncture and through a follow-up study, respectively. Risk differences (RDs) with 95% confidence interval (95% CI) were calculated. Results: Seven hundred three women were included with a mean follow-up at venepuncture of 10.8 months (range: 2.1 to 35.4 months). Five hundred twenty-one (74%) women stopped hormonal contraceptive use, 63 (9%) changed to a different preparation and 119 (17%) continued to use their preparation. One hundred forty-three (21%) of 682 women using a combined oral contraceptive at the thrombotic event were still using a combined preparation after the event. Women who continued their contraceptive use had less often a positive family history of venous thrombosis and more often surgery (RD 19% (95% CI: 9 to 30%)) or a plaster cast (RD 17% (95% CI: 3 to 34%)) at the thrombotic event than women who stopped. Out of 332 women using a combined preparation and who received advice from a physician to stop, 39 (12%) continued to use their current contraceptive. Conclusions: The finding that women continue their combined oral contraceptive use after receiving advice to stop is a real concern, in particular because this use could increase the risk of a recurrence. J Endocrinol Metab. 2014;4(3):56-63 doi: http://dx.doi.org/10.14740/jem221w