Does the patch cause deep vein thrombosis? Effectively communicating risk to your patients. (CME available)

Studies of the contraceptive patch and DVT have yielded conflicting results.  In 2006, two trials found a higher incidence of nonfatal blod clots among women using the patch than among women taking oral contraceptives, while a third study found no significant difference.  In 2010, a post-marketing surveillance study found no difference in DVT risk for women under age 40 who used the patch (compared with women on the pill).  Even if the true risk of DVT with the contraceptive patch is higher than with oral contraceptives, the absolute risk remains incredibly small.

How can we frame this discussion so that we communicate honestly without alarming patients?  Relative risk may exaggerate women's perception of a method's danger.  We should describe absolute risk instead, as a proportion using a consistent denominator.

For example, instead of saying, "the patch doubles your risk," we should say, "the risk of clots is 50 per 100,000 users of the pill, 100 per 100,000 users of the patch and 300 per 100,000 women with pregnancy.

Framing risk in this way helps us avoid inadvertently increasing our patients fears.

We appreciate your feedback! Please write us at pearls@reproductiveaccess.org with any questions, comments or additional resources to add to our list.

Sources

Jick SS., et al.  Postmarketing study of Ortho Evra and levonorgestrel oral contraceptives containing hormonal  contraceptives with 30 mcg of ethinyl estradiol in relation to nonfatal venous thromboembolism.  Contraception.  2010 Jan; 81 (1): 16 - 21.

Free CME credit

You can earn 1 free cme credit by completing this short quiz based on the content in this month's Contraceptive Pearl.  Answer the majority of questions correctly and you will receive a certificate documenting your CME credit.  CME granted by the American Academy of Family Physicians.

Just click on this CME Quiz and get started!