November 5, 2020

Hormones, Blood Clots and COVID-19: Should You Be Worried?

Get the answers from a vascular medicine specialist

woman holding hormone therapy birth control pills

Within the last few months, blood clots were added to the constantly changing list of COVID-19 symptoms. They’ve also been the source of COVID toes, breathing problems and a number of other medical conditions that have created even greater challenges for healthcare providers as they battle this devastating virus.


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The connection between COVID-19 and blood clots has created a new set of concerns for those who are pregnant, taking birth control or undergoing hormone therapy. But is there a reason to ditch the pills, patches, gels or go through pregnancy on edge? Vascular medicine specialist Meghann McCarthy, DO, explains the link between the coronavirus, blood clots and hormones, and also shares some advice for reducing the risk.

What are blood clots?

Blood clots are gel-like collections of blood that form in veins or arteries. They form when blood changes from liquid to partially solid. While clotting is a normal process, but clots can be dangerous when they do not dissolve on their own.

The link between hormones and blood clots

If you take birth control, you’ve heard the warnings about blood clots. But what causes them to occur and do they occur often?

Dr. McCarthy explains.

“Birth control and hormone therapy (in particular those containing estrogen) may increase the risk of blood clots, although the absolute risk in the general population remains low. The thought is that these hormones may affect some clotting factors produced by the liver, which in turn, can promote the development of blood clots.”

In addition to being on hormones, can certain medical conditions increase the likelihood of getting blood clots?

When coupled with hormone therapy, Dr. McCarthy says that additional factors may also increase the risk of blood clots. They can include underlying clotting disorders, a history of blood clots, vessel problems (like heart disease or stroke), high blood pressure, age, obesity and if you smoke.


Do certain forms of birth control or hormone treatments put users at a greater risk for blood clots?

“Hormone pills, injections, implants and intrauterine devices containing only progesterone have a lower risk of associated blood clots than forms which have an estrogen or estrogen-progesterone combination. Oral forms of estrogens tend to be associated with higher rates of blood clots than other forms of estrogen (patches or creams). Higher doses of estrogen, dosage changes with hormonal medicines or starting hormone therapy can also carry a higher risk,” says Dr. McCarthy.

Should pregnant people be worried?

According to Dr. McCarthy, hormonal fluctuations during pregnancy can cause clotting issues. However, the chances are pretty low for people who don’t have a history of blood clots.

“There are major fluctuations in the production of hormones during pregnancy. Pregnancy, like hormone medications, can also affect some of the clotting factors (proteins in the blood that help promote clotting) that are created by the liver and in turn, may increase the risk of getting blood clots. However, the risk of blood clots during pregnancy in a woman with no prior clotting history remains relatively low.”

Dr. McCarthy adds that people with a history of blood clots who are planning a pregnancy should consult with a healthcare provider who is familiar with this condition beforehand. They can determine if blood-thinning medications need to be incorporated into the plan as a safety precaution.

How could COVID-19 increase the risk of blood clots?

As stated earlier, COVID-19 has been shown to cause clotting throughout the body. Dr. McCarthy says that while COVID-19 may increase the risk of blood clots, the exact reason for this is unclear. At this point, it can’t be said that if you are on hormonal medication or pregnant, you’re at a greater risk for getting blood clots if you contract the coronavirus. But there are still some factors that we can watch out for.

“There are a number factors that may play into this risk, including injury/inflammation to the vessel wall (which leads to a buildup of cells around the injured wall and creation of a blood clot) and increased reactivity of the platelets (which are the clotting cells in the blood). The virus also affects inflammatory and coagulation (clotting) factors that circulate in the blood. This may increase the risk of blood clots.”


Dr. McCarthy adds that the risk of blood clots are likely related to a combination of how the body reacts to the virus (inflammation, vascular injury, changes in clotting factors, etc.) and things like immobilization in seriously ill, hospitalized patients who have COVID-19.

Should you stop taking hormones during the pandemic?

Dr. McCarthy stresses that it’s not a good idea to stop taking hormone medications without contacting your healthcare provider first. “Stopping therapy without talking to your doctor may lead to serious adverse health effects — and in the case of birth control pills — lead to the possibility of an unexpected pregnancy. I always recommend talking with your provider about the risks and benefits of stopping or changing therapy.”

How you can reduce the risk of getting blood clots

While alarming, it’s not exactly clear how common blood clots are with people who have mild cases of COVID-19. Researchers are still studying how the coronavirus affects the body. They’re also currently working on anti-blood clotting treatments to combat this symptom.

It may seem like getting blood clots is beyond our control, but Dr. McCarthy says there are things we can do lessen the risk.

“In general, the risk of blood clots can be reduced with regular activity or exercise, a healthy diet and watching your weight. If you plan to travel, stopping frequently to walk around during road trips, staying hydrated and wearing compression socks may help reduce the risk of clots. It is also important to keep up with age-appropriate cancer screenings like mammograms, pap smears and colonoscopies. Quitting smoking (or not even starting) can also help reduce the risk of blood clots and many other health problems. And like we’ve been doing since the pandemic started, it’s still important to follow guidelines regarding social distancing, hand hygiene and mask-wearing to reduce the risk of exposure to COVID-19.”

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