Blood Clots, Birth Control and Pregnancy: What Every Woman Should Know
Updated: Oct 16
Excerpt: Pregnancy, the months after birth and some types of birth control can all raise the risk of a blood clot. Here's why, which warning signs to watch for, and what to tell your care team.
In this article
Why pregnancy raises the risk
What birth control has to do with it
Warning signs to know
What to tell us at your visit
Frequently asked questions
October 13 was World Thrombosis Day, and it's a good reason to talk about something most women never think about. "Thrombosis" is the medical word for a blood clot that forms where it shouldn't, usually in a deep vein in the leg. That kind of clot can break loose and travel to the lungs, which is an emergency.
A few ordinary parts of life can raise your risk for a while, including pregnancy, the months after giving birth and certain types of birth control. I'm not telling you this to scare you. I want you to be able to spot the warning signs and give your care team the information they need.
Why pregnancy raises the risk
During pregnancy, your body naturally makes your blood clot more easily. That's a smart design, because it helps protect you from heavy bleeding during delivery. But it also means the risk of a clot goes up. According to the CDC, pregnancy raises the risk about fivefold, and it stays higher for about three months after delivery.
A C-section, bed rest and long stretches of not moving can add to that risk. That's one reason our prenatal and postpartum care includes so many questions, and why we encourage you to get up and move as soon as it's safe after delivery.
What birth control has to do with it
Birth control methods that contain estrogen, like the combined pill, the patch and the vaginal ring, slightly raise the chance of a clot. For most healthy women, the overall risk is still low, and it's lower than the risk during pregnancy.
But for some women, an estrogen-free option is the better fit. That includes women who:
Smoke, especially after age 35
Have had a blood clot before
Have a close family member who had a clot at a young age
Have certain clotting conditions, migraines with aura or high blood pressure
Recently had a baby
The good news is there are plenty of estrogen-free choices, including progestin-only pills, hormonal and copper IUDs, the implant and the shot. Our birth control page gives an overview, and we'll help you find the one that fits your health and your life.
Warning signs to know
Call us or get seen promptly if you notice, usually in one leg or arm:
Swelling
Pain, cramping or tenderness without an injury
Skin that feels warm or looks red or discolored
Call 911 right away if you have:
Sudden trouble breathing
Chest pain that gets worse when you breathe in or cough
A fast or irregular heartbeat, or coughing up blood
What to tell us at your visit
The best thing you can do is give us the full picture, even if it doesn't seem related. Let us know if you've ever had a blood clot, if anyone in your family has, if you smoke or vape, and if you have any long trips or surgeries coming up.
I'd much rather a patient tell me too much than too little. A family history of clots is exactly the kind of detail that changes which birth control I recommend.
If you're wondering whether your current birth control is still the right fit, or you're planning a pregnancy, let's talk it through together.
Schedule a visit or call (734) 242-2022.
Frequently asked questions
Does birth control cause blood clots? Birth control with estrogen slightly raises the risk, but for most healthy women the risk stays low. If you have other risk factors, an estrogen-free method is usually the safer choice.
Which birth control doesn't raise clot risk? Options without estrogen include the progestin-only pill, hormonal and copper IUDs, the implant and the shot. We'll help you weigh which one fits your health and lifestyle.
How long does clot risk stay higher after having a baby? The risk is highest in the first weeks after delivery and stays raised for about three months. Moving around as soon as it's safe and telling us about any leg swelling or pain both help.
Should I worry on a long car ride or flight? Long trips can add a little risk, especially during pregnancy or right after birth. Stand up and walk every hour or two, stretch your calves and drink plenty of water. If you've had a clot before, ask us before you travel.
References
Centers for Disease Control and Prevention. Understanding Your Risk for Blood Clots with Pregnancy.
About the author: Dr. Soudabeh Ahadi, MD, is a board-certified OB-GYN and the founder of Monroe OBGYN, where she has cared for women and families since 1982. She provides prenatal care, birth control counseling and family planning.
This post is for general education and isn't medical advice. If you have symptoms of a blood clot, seek care right away
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