Every once in a while you’ll see a “how awful” media story about a young woman who had a stroke or clot in her lungs that was ostensibly caused by oral contraceptive pills (OCPs). Lawyers are suing, OCP users are scared and I get lots of calls from concerned patients and parents. And then there are those ads that come on at night, often on non-network channels, that ask you to call a specific law firm if you have had “fill-in the blank” complications after taking Yaz or Yasmin or for that matter, any birth control pills. So although I have tried over the years to both reassure and address the pros and cons of birth-control pills to patients and concerned family members, unfounded and founded concerns remain. Hence I was delighted to see a new review in The Journal of Obstetrics and Gynecology titled ” Risk of Acute Thromboembolic Events With Oral Contraceptive Use”. The authors reviewed 6476 citations that reported on an association between exposure to oral contraception and outcomes of venous clots (thromboembolism), stroke and heart attack. They looked at every study’s design and quality as well the number of women who took OCPs and control women (who did not) and the number of years in which the women and controls were followed. In the end they found that 50 of the studies included the data that made them appropriate for their review.
Having given you ” the how they got to their conclusions”, I will skip the 7 dense pages of data and charts in the article… They found that there was a threefold increase in the odds of a venous thromboembolism diagnosis among current users of oral contraceptive pills compared to women who did not use OCPs. There was no evidence that the pills that had the progestin drosperinone ( found in Yaz, Yasmin and the generic equivalents) or other pills that had new second- generation progestins where associated with an increased risk of venous thromboembolism in many of the studies. Altogether, they did not find evidence for a difference in risk among the four types of progestins used in birth control pills. They also found a twofold increased risk of stroke from clot obstruction to cerebral vessels among current oral contraceptive pill users. But as they pointed out, the risk of a clot or stroke in pregnant and postpartum women is increased much more, threefold to eightfold that of non pregnant women. (In other words, a woman is far more likely to get a clot during pregnancy then she is using the pill to prevent pregnancy.) Additionally, there was no increase in heart attacks in women who took the pill when compared to women who did not.
The issue of whether OCPs that contain 20 ug of ethinyl estradiol or less (very low-dose pills) versus those that contain 35 ug (low dose pills) was not resolved because many of the studies did not distinguish between these two doses of birth control pills. The authors also pointed out that women who were high risk for clot formation because of heredity, obesity, previous clots or cardiovascular problems were less likely to get prescriptions for OCPs and hence the complication stats could be skewed.
So now when I’m asked, I can say yes, there is a slight increase in risk of clots with birth control pills but that risk of this complication is far greater during pregnancy. And I also want to remind women that birth control pills can regulate cycles, decrease cramps and heavy menstrual bleeding, treat acne, help overcome hormonal changes, reduce the risk of endometrial and ovarian cancer and of course prevent unwanted pregnancy. (But I should now add that there are other forms of contraception that are highly effective and for certain patients may be more appropriate, this is not an ad paid for by Ortho!)
The choice of OCP brand, amount of estrogen or type of progestin depends on a woman’s symptoms, side effects from previous use and her physician’s prescribing habits. This new analysis of multiple studies has shown that there is no difference between OCP types with regards to risk of thromboembolism. I hope the malpractice attorneys pay heed.