Low Dose Aspirin

What is low dose aspirin? Aspirin is also known as acetylsalicylic acid (pronounced uh-seet-l-sal-uh-sil-ik). It is a common prescription and over-the-counter medication that is similar to non-steroidal inflammatory (NSAIDs) like ibuprofen (Motrin®) and naproxen (Aleve®). Aspirin reduces inflammation, fever and pain. Aspirin can prevent the formation of blood clots which can make it useful in treating or preventing some conditions like heart attacks and strokes. The dosage for aspirin can range from 50 to 6000 milligrams (mg) per day depending on the condition being treated. Aspirin can also be used in combination with other medications. Low dose aspirin ranges from 60 to 150 mg daily but the usual dose taken during pregnancy is 81 mg daily. Regular strength aspirin is NOT a preferred pain reliever during pregnancy.


I just found out I am pregnant. Should I stop taking low dose aspirin?
Talk with your healthcare provider before making any changes to how you take this medication.

Does taking low dose aspirin increase the chance for miscarriage?
Miscarriage can occur in any pregnancy. Taking low doses of aspirin is not thought to increase the chance of miscarriage. Some studies have shown that taking low dose aspirin before conceiving may actually help lower the chance of miscarriage in some people who have had one or more previous miscarriages before 20 weeks of pregnancy. These findings are similar to studies that showed improved pregnancy outcomes people undergoing assisted reproductive technologies and were treated with low dose aspirin prior to implantation of the fertilized egg into the uterus.

Does taking low dose aspirin increase the chance of birth defects?
Every pregnancy starts out with a 3-5% chance of having a birth defect. This is called the background risk. Some studies have shown that taking high doses of aspirin during pregnancy can increase the chance for birth defects, but studies have not shown that taking low dose aspirin increases the chance for birth defects. Low dose aspirin is considered compatible in all trimesters of pregnancy when medically needed.

Could taking low dose aspirin cause other pregnancy complications?
Taking low dose aspirin as directed by a healthcare provider is not expected to cause other pregnancy complications. Studies have shown that low dose aspirin could improve pregnancy outcomes in some people by increasing blood flow and reducing inflammation or swelling in the uterus. Results from many studies have shown that low dose aspirin can lower the chances for preeclampsia (dangerously high blood pressure and pregnancy complications) in women who are at high risk for this condition. Only take low dose aspirin during pregnancy if your healthcare provider recommends it.

Does taking low dose aspirin in pregnancy cause long-term problems in behavior or learning for the baby?
There are not many studies about long-term effects for children exposed to low dose aspirin during pregnancy. However, studies have not found an increased chance for problems with physical or mental development in infants at 18 months of age. A study that looked at children up to 5 years of age who were born very early (before 33 weeks) and who were exposed to low dose aspirin during pregnancy did not find an effect on their learning or behavior compared to children who were not exposed to low dose aspirin during pregnancy.

Can I breastfeed while taking low dose aspirin?
Only small amounts of low dose aspirin enter the breast milk. The occasional use of low dose aspirin (75 mg daily to below 300 mg daily) is not expected to increase risks to a breastfeeding infant. Healthcare providers might recommend low dose aspirin in some people during breastfeeding to treat certain medical conditions. However, regular strength aspirin is not the pain reliever of choice during breastfeeding.
Aspirin eliminates from an infant's body more slowly than from an adult's body, so aspirin levels in the infant's body could build up over time with long-term use of aspirin. Using high dose aspirin can lower the body's ability to clot blood and, in some cases, could cause liver damage to the breastfeeding baby if it builds up in their body. This is not likely to happen with low dose aspirin.
Talk with your healthcare provider about your breastfeeding questions.

I take low dose aspirin. Can it make it harder for me to get my partner pregnant or increase the chance of birth defects?
There is very limited information about the effects of low dose aspirin on male reproduction. One study looked at men who attended an infertility clinic and were taking non-prescribed low dose aspirin at different doses and frequencies for at least six months. The study reported a decrease in the amount and quality of sperm, especially in those who used higher amounts of aspirin. Generally, it is not considered necessary for men to stop using low dose aspirin before trying to get their partner pregnant. However, men undergoing fertility treatment may want to talk with their healthcare providers about whether or not they need to stop taking aspirin.
In general, exposures that fathers or sperm donors have are unlikely to increase the risks to a pregnancy. For more information, please see the MotherToBaby fact sheet Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/. Disclaimer: MotherToBaby Fact Sheets are meant for general information purposes and should not replace the advice of your health care provider. MotherToBaby is a service of the non-profit Organization of Teratology Information Specialists (OTIS). Copyright by OTIS, October 1, 2020.