Earlier this week, the U.S. Centers for Disease Control and Food and Drug Administration caused a stir by recommending that distribution of the Johnson & Johnson COVID-19 vaccine pause after reports surfaced of six women experiencing a rare and severe type of blood clot after getting the vaccine. The news has sparked conversations on social media about blood clot risk, one of them revolving around birth control.
If this is news to you, here's what you need to know: On April 13, the CDC and FDA issued a joint statement recommending that health care providers temporarily stop administering the Johnson & Johnson vaccine. They'd received six reports of women who had experienced cerebral venous sinus thrombosis (CVST), a rare and severe form of a blood clot, in combination with low levels of blood platelets. (Two more cases have since emerged, one being a man.) These cases are noteworthy since the combo of CVST and low platelets shouldn't be treated with the typical treatment, an anticoagulant called heparin. Instead, it's crucial to treat them with non-heparin anticoagulants and high-dose intravenous immune globulin, according to the CDC. Because these clots are serious and the treatment is more complicated, the CDC and FDA recommended a pause on the Johnson & Johnson vaccine and are continuing to look into the cases before providing the next step.
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How does birth control factor into all of this? Twitter users have been raising a virtual eyebrow at the CDC and FDA's call for a pause on the vaccine, highlighting the increased risk of blood clots associated with hormonal birth control. Some of the tweets compare the number of cases of CVST out of everyone who's received the Johnson & Johnson vaccine (six out of nearly 7 million) to the rate of blood clots in people on hormonal birth control pills (about one in 1,000). (Related: Here's How to Get Birth Control Delivered Right to Your Door)
On the surface, the risk of blood clots associated with birth control seems far more significant than the risk of blood clots associated with the J & J vaccine — but comparing the two is a bit like comparing apples to oranges.
"The type of blood clots that may be linked to the vaccine appear to be due to a different cause than those associated with birth control," says Nancy Shannon, M.D., Ph.D., primary care physician and senior medical advisor at Nurx. The post-vaccine cases that the FDA and CDC have zeroed in on include instances of CVST, a rare type of blood clot in the brain, alongside low platelet levels. On the other hand, the type of clots commonly associated with birth control are deep vein thrombosis (clotting in major veins) of the legs or lungs. (Note: It is possible for hormonal birth control to cause blood clots of the brain, especially among those who experience migraines with aura.)
Deep vein thrombosis is typically treated with blood thinners, according to The Mayo Clinic. CVST, however, is rarer than deep vein thrombosis, and when seen in combination with low platelet levels (as is the case with the J & J vaccine), requires a different course of action than the standard treatment of herapin. In these cases, abnormal bleeding occurs in combination with the clots, and heparin could actually make matters worse. This is the CDC and FDA's reasoning behind suggesting a pause on the Johnson & Johnson vaccine.
Regardless of whether you can directly compare the two, it's important to discuss the risk of blood clots associated with taking birth control, and it's something worth looking into if you're already on or considering BC. "For a woman with no underlying medical conditions or risk factors that suggest she's more likely to experience a clot, the risk of developing a blood clot is three- to five-fold increased while on combined hormone contraception compared to women not on any form of contraception," says Dr. Shannon. For perspective, the rate of blood clots among non-pregnant reproductive-age women who don't use hormonal birth control is one to five out of 10,000, but among non-pregnant reproductive-age women using hormonal birth control, it's three to nine out of 10,000, according to the FDA. (Related: Can Antibiotics Make Your Birth Control Less Effective?)
An important distinction: Blood clots are associated with estrogen-containing birth control specifically. "When we talk about blood clot risk in relation to birth control, we're only talking about birth control that contains estrogen, which includes combination birth control pills [i.e. pills that contain estrogen and progestin], birth control rings, and the birth control patch," says Dr. Shannon. "Hormonal birth control that only contains the hormone progestin doesn't pose this increased risk. Progestin-only forms of birth control include progestin-only pills (sometimes called minipills), the birth control shot, the birth control implant, and the progestin IUD." Since that's the case, your doctor might steer you toward a progestin-only method if you want to go on birth control but have factors that might make you more prone to clots, such as being 35 or older, a smoker, or someone who experiences migraine with aura.
Even with combined hormone birth control, the risk of clotting is "still quite low," says Dr. Shannon. Still, it's not something to take lightly, since when the clots do occur, they can be life-threatening if not diagnosed promptly. So, it's especially important to know the signs of a blood clot if you're on BC. "Any swelling, pain, or tenderness in a limb, particularly a leg, should be checked out immediately by a doctor as that can be a sign that a blood clot has formed," says Dr. Shannon. "Signs that a clot may have traveled to the lungs include difficulty breathing, chest pain or discomfort, fast or irregular heartbeat, lightheadedness, low blood pressure, or fainting. If anybody experiences this they should head straight to the ER or call 911." And if you develop a migraine with aura after starting birth control, you should definitely tell your doctor. (Related: Hailey Bieber Opened Up About Having "Painful" Hormonal Acne After Getting an IUD)
And, for the record, "people using birth control pills, patches, or rings who have received the Johnson & Johnson vaccine should not stop using their contraception," says Dr. Shannon.
It might be more useful to compare the risk of blood clotting with birth control and the COVID-19 vaccine to that of what they're designed to prevent. The risk of blood clots during pregnancy is "significantly higher than that posed by birth control," says Dr. Shannon. And a University of Oxford study suggests that the risk of getting cerebral venous sinus thrombosis is actually higher among those infected with COVID-19 than those who received the Moderna, Pfizer, or AstraZeneca vaccines. (The study did not report on the rate of cerebral venous sinus thrombosis among people who'd had the Johnson & Johnson vaccine.)
Bottom line? The recent news shouldn't stop you from booking a vaccine appointment or talking through all your birth control options with your doctor. But it pays to be educated on all the potential risks of both, so you can properly keep tabs on your health.
The information in this story is accurate as of press time. As updates about coronavirus COVID-19 continue to evolve, it's possible that some information and recommendations in this story have changed since initial publication. We encourage you to check in regularly with resources such as the CDC, the WHO, and your local public health department for the most up-to-date data and recommendations.