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You may have heard about doctors prescribing so-called “baby aspirin” to folks who’ve had a heart attack to possibly prevent stroke and future cardiac events. But did you know that taking low-dose aspirin can be a game-changer for expecting parents, too? A lot of people don’t. In fact, only 20% of families are extremely or very aware that medical interventions, like taking low-dose aspirin in pregnancy, are readily available to reduce the risks of preeclampsia, a serious pregnancy complication affecting about 1 in 25 expectant parents in the U.S. Keep reading to learn which parents-to-be can benefit from this magical pill.

What is low-dose aspirin?

Low-dose aspirin—aka “baby aspirin”—is a nonsteroidal anti-inflammatory drug (NSAID) that typically contains a daily dose of 60 to 150 milligrams, whereas a standard dose contains about 325 milligrams. Low-dose aspirin gets its “baby aspirin” nickname because of the lower dose—NOT because it’s safe for kids! Avoid giving aspirin-containing meds to anyone under 19, unless recommended by a healthcare provider.

How does aspirin work?

Aspirin works by literally blocking certain enzymes in your body. In addition to reducing pain and inflammation, this action prevents blood clotting. (Blood clots are gel-like masses that form in your veins and arteries.) That aspirin-fueled barrier also forces some fats in your body to take a different path, which in turn, creates substances that further help reduce inflammation.

Benefits of Low-Dose Aspirin in Pregnancy

Low-dose aspirin has pretty powerful anti-inflammatory and blood-thinning properties that may improve blood flow. By boosting blood flow to the uterus low-dose aspirin can help certain babies-to-be get the oxygen and blood flow they need to thrive…and survive.

Low-Dose Aspirin in Pregnancy and Preeclampsia

The biggest benefit of taking low-dose aspirin in pregnancy is its ability to help delay and prevent the onset of preeclampsia. Preeclampsia is a serious pregnancy complication marked by high blood pressure, protein in the urine, and severe swelling (this is why you may be asked to pee in a cup during prenatal appointments). Research shows that, for certain parents-to-be, taking low-dose aspirin in pregnancy reduces the risk of preeclampsia by 15%. Preeclampsia happens in 5 to 8% of pregnancies, usually after 20 weeks. Although preeclampsia is potentially a very serious condition, most with preeclampsia go on to deliver healthy babies.

Other Potential Benefits of Low-Dose Aspirin in Pregnancy

While low-dose aspirin appears to show promise in other areas of prenatal care, the American College of Obstetricians and Gynecologists (ACOG) remains steadfast that there’s insufficient evidence to back low-dose aspirin’s role in preventing…

  • Preterm Birth: Even though a 2020 report looking at about 12,000 pregnant individuals found that low-dose aspirin reduces the risk of preterm birth (before 37 weeks) by 11%—and early preterm birth (before 34 weeks) by 25% in first-time mothers—ACOG does not advise using low-dose aspirin to prevent spontaneous preterm birth in the absence of risk factors for preeclampsia.

  • Fetal Growth Restriction: For parents-to-be at risk of preeclampsia, preventative low-dose aspirin in pregnancy may reduce the chance of fetal growth restriction, but it’s not recommended for those without that risk factor.

  • Still Birth: Some non-randomized studies have found low-dose aspirin in pregnancy may prevent repeat stillbirths, but evidence from randomized controlled trials—the gold standard in research—has yet to replicate those results.

Who should take low-dose aspirin in pregnancy?

Healthcare professionals usually only recommend low-dose aspirin for pregnant people if they have a higher chance of developing preeclampsia or other complications. That means low-dose aspirin in pregnancy may be helpful for those with…

  • Autoimmune diseases, such as lupus

  • Blood clotting disorders

  • Multiples

  • Diabetes

  • High blood pressure

  • History of preeclampsia

  • History of preterm delivery

  • Kidney disease

Certain stressors, like low income, no access to health care, and experiencing racism, can increase the risk for preeclampsia as well. One, two, or more of the following moderate risk factors may warrant the use of low-dose aspirin in pregnancy:

  • Black

  • Body mass index (BMI) of 30 or higher

  • Family history of preeclampsia

  • In vitro fertilization

  • Over 35 years old

  • Prior babies with low-birthweight

  • Under 18

Risks of Taking Aspirin in Pregnancy

Taking low-dose aspirin as recommended by a healthcare provider is considered safe for most pregnant people and has not been shown to increase pregnancy-related complications, such as preterm delivery, low birth weight, or congenital anomalies. However, taking a higher dose of aspirin has been associated with pregnancy loss, congenital defects, premature closure of a vessel in the fetus’s heart, and bleeding in the brain of premature infants. Always follow your doctor or midwife’s instructions.

Who should avoid low-dose aspirin in pregnancy?

Expecting parents with the following conditions should avoid low-dose aspirin in pregnancy:

  • Active peptic ulcer disease

  • Aspirin allergy

  • Asthma with history of aspirin-induced acute bronchospasm

  • Gastrointestinal or genitourinary bleeding

  • Hypersensitivity to NSAIDs

  • Hypersensitivity to other salicylates

  • Nasal polyps

  • Severe hepatic dysfunction

How to Take Low-Dose Aspirin Safely

Experts from ACOG, the Society for Maternal-Fetal Medicine and the U.S. Preventive Services Task Force suggest parents-to-be who are at risk for preeclampsia begin a low-dose aspirin regimen (usually 81 milligrams daily) between 12 and 28 weeks of pregnancy—ideally starting before 16 weeks. With their doctor’s go-ahead, those expecting parents typically take low-dose aspirin daily until at least 36 weeks.

Aspirin in Pregnancy: Final Thoughts

While taking low-dose aspirin can be an important precaution for those at risk for preeclampsia, it’s not advised unless you have certain medical conditions. So, don’t take aspirin in pregnancy “just in case!” Instead, talk to your care team to find out if you’re a good candidate for low-dose aspirin in pregnancy.

  

More Prenatal Insights:

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REFERENCES  
  • March of Dimes: March of Dimes Launches “Low-Dose, Big Benefits” Campaign to Combat Preeclampsia and Preterm Birth
  • Mother To Baby, Fact Sheets (OTIS): Low Dose Aspirin
  • National Health Service (NHS): Who can and cannot take low-dose aspirin
  • Stanford Children’s Health: Reye Syndrome in Children
  • Salicylic Acid (Aspirin) StatPearls. January 2024 
  • Cleveland Clinic: Blood Clots
  • Aspirin Use to Prevent Preeclampsia and Related Morbidity and Mortality: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force, JAMA, September 2021
  • Low-dose aspirin for the prevention of preterm delivery in nulliparous women with a singleton pregnancy (ASPIRIN): a randomised, double-blind, placebo-controlled trial. The Lancet. January 2020
  • American College of Obstetricians and Gynecologists (ACOG): Low-Dose Aspirin Use During Pregnancy
  • Recurrent miscarriage--an aspirin a day? Human Reproduction. October 2020
  • Preeclampsia Foundation: Ask About Aspirin
  • March of Dimes: Preeclampsia
  • Mayo Clinic: Is it safe to take aspirin during pregnancy?
  • Low-dose aspirin use for the prevention of morbidity and mortality from preeclampsia: U.S. Preventive Services Task Force recommendation statement. Annals of Internal Medicine. December 2014
  • U.S. Preventive Service Task Force: Aspirin Use to Prevent Preeclampsia and Related Morbidity and Mortality: Preventive Medication
  • March of Dimes: Low dose aspirin during pregnancy: What you need to know
  • Mayo Clinic, Pregnancy week by week: Is it safe to take aspirin during pregnancy?

About Holly Pevzner

Holly Pevzner is Happiest Baby’s Staff Writer. She specializes in creating parenting, pregnancy, health, nutrition, and family travel content. Her work—including essays, columns, reported features, and more—has appeared in outlets such as EatingWell, Family Circle, Parents, Real Simple, and The Bump. Before becoming a full-time writer, Holly held senior staff positions at Prevention, Fitness, and Self magazines, covering medical health and psychology. She was also a contributing editor at Scholastic Parent & Child magazine and a regular kids-health columnist for Prevention and First For Women magazines. Holly lives in Los Angeles with her husband, two boys, and terrier mix.

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Disclaimer: The information on our site is NOT medical advice for any specific person or condition. It is only meant as general information. If you have any medical questions and concerns about your child or yourself, please contact your health provider.