Birth control pills, also known as oral contraceptives, are a highly effective and widely used method of preventing pregnancy. In the United States, about 12 million people between the ages of 15 and 49 rely on birth control pills. While generally safe, as with any medication, certain risks are involved. 

There are several different kinds of birth control pills, each with its unique benefits and formulation. They’re categorized into two categories: combined oral contraceptives and progestin-only pills, also called mini-pills.

“For some women, combined oral contraceptives, which contain estrogen and progestin, can carry a higher risk of stroke,” says Nebraska Medicine vascular neurologist Kelly-Ann Patrice, MBBS. “High doses of estrogen can increase the likelihood of clot formation, and lead to strokes.” 

This is an important consideration when choosing a birth control method, as the risk may vary depending on individual health factors, such as age, smoking status or pre-existing conditions.

How can birth control increase stroke risk?

Estrogen in certain birth control pills can increase the risk of stroke through its effects on blood vessels, blood clotting and blood pressure. Specifically, estrogen can increase the production of clotting factors, which makes the blood more prone to clot formation. If a clot forms in the brain’s blood vessels, it can block the flow of oxygen-rich blood, leading to an ischemic stroke, a type of stroke caused by a blockage in a blood vessel.

Blood pressure is also a risk factor for stroke. Studies show estrogen can dilate blood vessels and help maintain normal blood pressure levels. If it’s taken in high doses, like with some birth control pills, estrogen can elevate blood pressure in some people. 

While the overall risk of stroke for people taking estrogen-containing birth control is about 8 in 100,000, it's important to note that the risk is relatively low. However, the risk may increase for individuals who have other pre-existing conditions like high blood pressure, smoking, or a history of blood clots.

“The good news is that most of the studies on birth control and stroke risk were conducted when pills contained higher doses of estrogen,” says Dr. Patrice. “Today, modern birth control pills contain much lower doses of estrogen, which means they carry a lower risk of stroke compared to older formulations.” 

What can increase the risks of stroke on birth control? 

Several factors can amplify the effects of estrogen on stroke risk:

• Smoking increases the likelihood of developing blood clots. 
• Being over the age of 35, you have a higher risk of stroke, especially if you smoke.
• Hypertension or high blood pressure.
• Migraines with aura.
• History of blood clots or a predisposition to clotting disorders.

“If you have a prior history of stroke, taking estrogen containing birth control could potentially increase your risk of having another stroke,” says Dr. Patrice. “It is recommended that anyone with these increased risk factors take progestin-only or nonestrogen birth control methods.”

What are some stroke symptoms to be aware of?

A stroke occurs when a blood vessel carrying oxygen and nutrients becomes blocked or bursts. An acronym promoted by the American Stroke Association is B.E.F.A.S.T. and helps people recognize the symptoms of stroke: 

• Balance – Loss of balance of coordination.
• Eyes – Blurred or double vision or loss of vision.
• Face – Drooping on one side of the face.
• Arm – Weakness or numbness in arms or legs. 
• Speech – Difficulty speaking or slurred speech.
• Time – Time to call 911 immediately.

Talk to your provider about different birth control options.

If someone is concerned about stroke risk, discussing options with your health care provider is important. There are several birth control alternatives to consider that may be safer for those with a higher stroke risk. Nonhormonal methods such as a copper IUD, diaphragms and progestin-only contraception are popular alternatives to estrogen-containing options. Additionally, making lifestyle changes – such as exercising, quitting smoking and adopting a healthy diet – can lower the overall risk of stroke. 

“Each person’s risk factors are unique, so an individual assessment is key,” explains Dr. Patrice. "I recommend speaking with your primary care doctor or OB-GYN to discuss any concerns and explore which birth control methods would best suit your health needs." 

Dr. Patrice emphasizes that birth control is generally safe but factors like age and pre-existing health conditions can affect individual risks, so it's important to be informed and proactive about your options.