Women who don’t smoke take birth controls, and so do women who smoke–and they have a higher blood clot risk.

However, nonsmoking women are STILL at an increased risk for a blood clot simply due to the birth control pills.

You’ve often heard that birth control pills raise blood clot risk in women who smoke.

But what about blood clot risk in nonsmoking women who use birth control pills?

I wondered about this and asked Randy Fink, MD, Director of the Center of Excellence for Obstetrics & Gynecology in Miami, FL. I assumed that something inherent in the birth control pills raised blood clot risk for any female, smoking or nonsmoking.

Dr. Fink explains: “Deep vein thrombosis and pulmonary embolus – a blood clot that travels to the lungs – are called thromboembolic events. Consider the rate of blood clots in women who are not on hormonal birth control.

“The common estimate is that it happens in 5 to 10 cases per 100,000 woman-years. {A more recent study even suggests it happens much more frequently: 50 to 100 cases per 100,000 woman-years.} 

“On hormonal birth control, a clotting complication is said to occur in 20 to 30 cases per 100,000 woman-years. This is clearly higher than the 5-10 per 100,000 for women not on birth control.

“So, while the increase may seem frightening, the risk of these same clotting complications occurring during pregnancy is 60-96 per 100,000. During the postpartum period, it is 511 per 100,000 woman-years!”

Why is the blood clot risk so much higher postpartum? “Pregnancy and the postpartum are associated with the classic risk triad for blood clots. First, blood ‘stagnates.’ Pregnancy changes the flexibility of blood vessels by making them swollen.

The pregnant uterus sits on and compresses the giant blood vessel that is the final pipe leading to the heart (the vena cava) from all the smaller veins. Blood therefore tends to pool.

“The swollen vessels sustain temporary damage, which is the second factor: injury to the muscular walls of these vessels. Finally, pregnancy itself is a hypercoagulable state.

There is a natural increase in several clotting factors, and a decrease in function of the systems our bodies use to break down clots.

A good explanation for this is so that the body does not form small clots that decrease the flow of blood (thus oxygen & nutrition) to the placenta & the baby.

“So, while birth control is not without risk (for blood clots), the risk of pregnancy itself is clearly much higher. Thus, hormonal birth control is said to be a safe way to avoid an unintended pregnancy.”

If, despite being a nonsmoker, you’re still concerned about blood clots because you are taking birth control pills, you can significantly lower risk of blood clots by 1) exercising daily and including sessions of intense exercise several times/week, 2) ensuring your blood pressure is normal, 3) managing stress and 4) eating a plant-based diet.

Creating an environment where the very best of medicine and gentle gynecology are practiced and where patients come first has always been Dr. Fink’s goal.
Lorra Garrick has been covering medical, fitness and personal/cybersecurity topics for many years, having written thousands of articles for print magazines and websites, including as a ghostwriter. She’s also a former ACE-certified personal trainer.