Baby aspirin: doses, uses, and side effects

Don’t let the name fool you—baby aspirin is not for babies. 

Baby aspirin is low-dose aspirin, usually given as an 81 mg daily dose. Aspirin is a type of NSAID (a non-steroidal anti-inflammatory drug) typically used as a common pain killer. These drugs work by blocking inflammation in the body, which can cause symptoms like fever and pain. You may have taken aspirin for fever or pain relief before. But the amount of medication in baby aspirin isn’t high enough to alleviate these symptoms, so why take it?

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Unlike high-dose aspirin used to treat things like fever, swelling, and pain, baby aspirin has traditionally been used to prevent disease. This lower dose still has anti-inflammatory effects on the body but carries a lower risk of side effects compared to higher dosages. 

Some healthcare professionals recommend baby aspirin to protect against the following conditions:

Heart disease

For people who have had a heart attack before, some healthcare providers and the FDA (U.S. Food and Drug Administration) recommend low-dose aspirin to prevent future heart attacks (FDA, 2015). 

Some studies suggest that baby aspirin lowers the risk of heart attacks in people who haven’t had a heart attack, too. One analysis found that low-dose aspirin reduces the risk of non-fatal heart attacks by about 12% (ATT, 2009). A review of data from over 160,000 patients showed similar results (Abdelaziz, 2019). 

But while baby aspirin may have clear benefits when it comes to preventing heart attacks, it’s not without risks. Because of how aspirin works, it can increase a person’s risk of bleeding. These side effects can be serious, and the U.S. Preventive Services Task Force found that the risk of side effects outweigh the possible benefits of taking daily aspirin. 

They, therefore, recommended that healthcare providers not routinely recommend baby aspirin to prevent a first heart attack (U.S. Preventive Services Task Force, 2021). 

Blood clots and stroke

People with conditions like diabetes, high cholesterol, and high blood pressure have a higher risk of clogged blood vessels or deadly blood clots. 

Aspirin can prevent your blood from clumping together and forming clots in your blood vessels. This keeps them from becoming blocked, improving blood flow throughout the body and helping prevent heart attacks and stroke. 

If a blood clot reaches the brain it can cut off the oxygen supply there, causing something known as an ischemic stroke. People who have had this type of stroke in the past may be told to take aspirin to lower their risk of experiencing another stroke. Some studies estimate the risk of a second stroke decreases by 22% in people who take aspirin for prevention (Oza, 2017). 

Some healthcare providers have recommended aspirin for the prevention of a first stroke. However, due to the risk of side effects, this recommendation may be changed in the future (U.S. Preventive Services Task Force, 2021). 

Kawasaki disease

Kawasaki disease is an inflammatory condition more common in children. People with Kawasaki disease are at high risk for severe blood vessel damage around the heart. Low-dose aspirin is given to reduce this damage and avoid blood clots in those at-risk.Kawasaki disease is the only reason that aspirin is ever given to children, and it should only be used under the guidance of a healthcare provider. If your child has a headache or a fever, never give them aspirin, even in small doses. That’s because aspirin can cause very serious side effects in children, including liver damage, brain damage, and death.

Cancer

Some research suggests that people who take low-dose aspirin over five years have a lower risk of colon cancer. One review, including data from over 25,000 people, noted that daily low-dose aspirin also decreased the risk of cancers outside the digestive system, including brain, lung, and prostate cancers (Rothwell, 2011). 

Baby aspirin for cancer prevention is an off-label use, meaning that the FDA did not explicitly approve it for this purpose. However, some healthcare professionals might recommend this route if it’s appropriate for their patient’s needs. 

Not all of the data on aspirin use and cancer is clear. One large clinical trial found an increased risk of cancer in adults over 70 who took daily baby aspirin (McNeil, 2018). The U.S. panel states that providers should no longer recommend baby aspirin for cancer prevention (U.S. Preventive Services Task Force, 2021). 

Pregnancy complications

Baby aspirin is sometimes used off-label to prevent issues during pregnancy, such as preeclampsia. Preeclampsia is a condition that causes very high blood pressure, which is dangerous for both mother and baby. Low-dose aspirin can be used to prevent this condition (ACOG Committee, 2018).

Researchers have also studied baby aspirin as a protective method for premature birth. A clinical trial of almost 12,000 pregnant people found that low-dose aspirin reduced the risk of both premature birth and newborn death (Hoffman, 2020). Because it’s still only for off-label use, more data is needed before it’s routinely recommended. 

As is the case with higher doses of aspirin, low doses can also damage the delicate lining of your stomach and increase the amount of acid produced there, leading to heartburn, mild stomach upset, and other gastrointestinal issues. It can also increase the risk of developing an ulcer which can cause pain and bleeding (Kitay, 2019). 

Aspirin is used to reduce the risk of blood clots, but by the same token, it increases the risk of bleeding. People who take aspirin or other blood thinners regularly are at an increased risk for bleeding in their digestive tract and elsewhere in their bodies. Although the risk is smaller in those taking low-dose aspirin compared to higher doses, continuous use of baby aspirin still increases the risk of bleeding (Hall, 2014; Sutcliffe, 2013).

Long-term aspirin use can also lead to kidney or liver damage in adults. It is always important to speak to a healthcare professional before starting a medication. 

As mentioned previously, aspirin cannot be given to children or babies. That’s because it can cause a condition called Reye’s syndrome, especially when given to children experiencing a viral illness, like the flu or chickenpox. Reye’s syndrome causes severe damage to cells in the liver and kidneys, which can be deadly.

Baby aspirin interacts with certain other medications. For example, if you take an anticoagulant or blood thinner, low-dose aspirin can increase the risk of bleeding. If you’re taking it with another type of NSAID like ibuprofen, it increases the risk of damage to the digestive system, liver, and kidneys. 

People with certain underlying health conditions, including the ones listed below, should avoid aspirin (FDA, 2015):

• History of bleeding (from the stomach or intestinal ulcers, for example) 

• Kidney or liver disease

• Bleeding disorders, such as hemophilia or a vitamin K deficiency

Baby aspirin is great at protecting you from specific health conditions, like a second heart attack or stroke, so many individuals benefit from using it as a preventive measure. 

However, even though it’s safer than high-dose aspirin, it’s not without risks. Recent recommendations advise against taking daily baby aspirin to prevent first heart attacks, first strokes, or cancer. It’s important to speak to a healthcare professional to decide whether low-dose aspirin therapy is right for you.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

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Current version

January 13, 2022

Written by

Gina Allegretti, MD

Fact checked by

Yael Cooperman, MD

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About the medical reviewer

Yael Cooperman, MD, Ro

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.