Like millions of women, Colleen Wachob had been the pill for years without incident. At 32 years old, she was exceptionally healthy—she didn’t smoke, ate a plant-based diet, and did yoga six times per week, she writes in mindbodygreen.
After a Saturday morning yoga class, she was doing some window shopping with a friend when she started to feel tired and short of breath. When the weird feeling didn’t go away, she decided to head home. She spent the rest of the weekend sleeping.
At her doctor’s office on Monday, her GP conducted a ECG and asked some follow-up questions. Believing that she’d suffered a pulmonary embolism, he sent her to the emergency room right away, where a chest x-ray, leg ultrasound, CT scan, and blood tests confirmed his suspicion. Wachob was given a prescription for blood thinners, and spent the next three months recovering.
She was lucky—pulmonary embolisms are often fatal. One study reported that in 25% of cases, pulmonary embolisms result in sudden death.
A pulmonary embolism begins with deep vein thrombosis (DVT), also known as a blood clot. DVT often occurs in the veins of the legs, causing cramps and swelling, which may be early signs that something is wrong. If it breaks away, it can move through the bloodstream to the lungs, where it can block an artery.
Contraceptive pills that contain estrogen increase the risk of these blood clots. This risk is higher for women who smoke, are overweight, or are over 35.
But doctors underline that when it comes to blood clots, pregnancy actually presents a substantially higher risk than taking the pill.
Still, in the United States, the chances of getting a blood clot while taking the birth control pill are not well documented. Blood clots can happen to anyone, but few recent studies have identified the specific risks associated with oral contraceptives.
A study conducted in the Netherlands found that the “currently available oral contraceptives increased the risk of venous thrombosis fivefold compared with non-use.” The risk was found to differ according to the estrogen dose and the type of synthetic progestogen.
Another study followed Danish women of childbearing age from 1995 to 2005. Researchers found that women who used birth control pills were twice as likely to experience a blood clot. Though blood clots affected less than 0.001 % of pill users in the sample, it was still a risk—and in some cases, a fatal one.
If you’re worried, you can ask your doctor to screen you for Factor 5 Leiden, a genetic mutation that predisposes you to blood clots. It’s worth getting screened—approximately 5% of all Caucasian women have it and studies have found that it significantly increases the risk of DVT. Pregnant women are routinely screened for it.
This isn’t a warning to avoid the pill, but rather a reminder that there are still risks involved, even if most of your girlfriends are on it. If you’re an otherwise healthy non-smoker, you can’t do much to avoid blood clots, but it may help to know the symptoms of DVT and pulmonary embolism.
It’s also a good idea to spend some time researching other side effects of the pill—including decreased sex drive and an increased risk of some cancers. Remember, the pill doesn’t protect against STIs and is only effective when taken correctly.
Knowing the risks can help you to make the best decision for your life and your health.
