birth control pills (birth control and blood clots)Many women evaluate birth control options based on ease of use, rate of failure, and types of side effects. Birth control is supposed to make your life easier and help you make the best choices for your health and well-being.

But if you or members of your family have a history of blood clot or stroke, the wrong type of birth control could complicate your life and possibly even cause great harm. How? Because some types of birth control may increase your risk of blood clots, especially if you have a genetic predisposition for suffering them.

Blood clots and birth control

Hormonal birth control (your pill, shot, ring, patch, and implant options) comes in two types — estrogen based and progestin based. Estrogen-based birth control can increase your chance of forming an abnormal blood clot significantly. According to the National Blood Clot Alliance, it may increase one’s chances three- or four-fold. Estrogen elevates clotting factors in the blood, thus possibly causing abnormal blood clotting. (Abnormal blood clotting means any clot you don’t want to form. When you suffer a cut, yes, you want your blood to clot. But other times, you don’t necessarily want your blood to clot.)

If you don’t have any other risk factors for blood clots, your chances of hormonal birth control causing an abnormal blood clot is still very small. However, if you have high blood pressure, past incidents of abnormal blood clots, or a genetic blood clotting disorder such as factor V Leiden, a hormonal birth control pill could push your chances of suffering a blood clot over the edge.

Finding out if you have a genetic blood clotting disorder

How do you even find out if you have a blood clotting disorder like factor V Leiden? Testing for factor V Leiden isn’t done on a regular basis, but here in a medical research hub like Boston, it’s becoming more common. I happened to be sharing my family’s blood-clot-and-stroke-filled medical history with a new physician when she mentioned that her colleague was doing research related to a genetic clotting disorder — and that I’d be a good candidate for testing.

I underwent a simple blood test, and it came back that I had heterozygous factor V Leiden, the most common version of the disorder. This means I carry one copy of the mutation, and it was passed on from one of my parents. Carrying two copies is fairly rare, but it does increase your chances of abnormal blood clots and stroke even more significantly.

Your options

With that knowledge, my doctors guided me away from any estrogen-based birth control option and steered me towards progestin-only ones. While many estrogen-based options include progestin, it is key to find birth control that only includes the latter. The mini-pill (Micronor) and Depo-Provera are two of the options that contain only progestin.

Are those options as effective as an estrogen-based pill? No, but they are close. And when you’ve seen way too many family members around you suffer from stroke and deep vein thrombosis, it’s worth the peace of mind that you are taking any steps you can to avoid the same fate.

Kat Cornetta
Kat grew up in Rochester, NY, and attended college in Ithaca and Binghamton, NY. She moved to Boston to earn a graduate degree in educational administration. In addition to her career in education, Kat has a part-time freelance sportswriting career covering women’s college hockey, gymnastics, and figure skating. She contributed to the Boston Herald for a decade before moving over to the Boston Globe, where she wrote their first-ever weekly women’s college hockey notebook. Her long-term career goal is to write a book. An Ipswich resident, Kat is a mother to two sons (born in 2016 and 2018) and owns a cat named after legendary Buffalo Bills head coach Marv Levy. After having her sons in 2016 and 2018, Kat is attempting to balance a full-time job in education with her writing dream and motherhood. She loves coffee, cats and 1990s NFL quarterbacks. She dislikes chewing gum, high shelves and baby pajamas that snap instead of zipper. You can read her work at sportsgirlkat.com