Pregnancy check
Preeclampsia risk factors: should I take low-dose aspirin?
Preeclampsia is one of the most serious problems in pregnancy. Low-dose aspirin lowers the chance of it for people at high risk. Tick what applies to you to see where you fall in the USPSTF risk table.
Your pregnancy and health
For people who are pregnant or planning a pregnancy. Nothing you tick leaves this page.
What you will see
Your risk level in the USPSTF table and what it says about low-dose aspirin.
Educational only, not medical advice. Take aspirin in pregnancy only if your doctor or midwife advises it.
Source
US Preventive Services Task Force, September 2021 recommendation on aspirin use to prevent preeclampsia, Table 1 (clinical risk assessment).
Validated in
Pregnant people without symptoms of preeclampsia and with no prior adverse events with low-dose aspirin.
Limits
It uses only risk factors from your medical history and does not give a percentage risk. It cannot tell whether you have preeclampsia now: if you feel unwell during pregnancy, contact your care team.
The USPSTF risk table
| Risk level | Risk factors | Advice |
|---|---|---|
| High | Preeclampsia before, especially with a bad outcome; twins or more; chronic high blood pressure; type 1 or 2 diabetes before pregnancy; kidney disease; autoimmune disease such as lupus or antiphospholipid syndrome | Low-dose aspirin if 1 or more applies |
| Moderate | First birth; prepregnancy BMI over 30; mother or sister had preeclampsia; Black; lower income; age 35 or older; personal history (low birth weight or small baby, earlier bad outcome, more than 10 years since last pregnancy); in vitro conception | 2 or more may also benefit |
| Low | Earlier uncomplicated full-term delivery | Aspirin not recommended |
The USPSTF recommends low-dose aspirin, 81 mg a day, after 12 weeks of pregnancy for people at high risk of preeclampsia (grade B) (USPSTF 2021). Each high-risk factor alone is consistently linked with the greatest risk: preeclampsia would likely occur in at least 8% of pregnancies with one of them (USPSTF 2021). Moderate-risk factors are linked with more risk, some more consistently than others, and several together can add up to a higher risk (USPSTF 2021).
Being Black and having a lower income are on the list because of environmental, social and historical inequities, including access to health care, not biology (USPSTF 2021).
What preeclampsia is
Preeclampsia is one of the most serious health problems in pregnancy. It affects about 4% of pregnancies in the US and can harm both parent and baby. It also accounts for 6% of preterm births in the US (USPSTF 2021).
When aspirin is started
The USPSTF advice is to start after 12 weeks (USPSTF 2021). The American College of Obstetricians and Gynecologists, as summarized by the USPSTF, recommends starting between 12 and 28 weeks, ideally before 16 weeks, and continuing daily until delivery (USPSTF 2021). In the trials the USPSTF reviewed, daily low-dose aspirin in pregnancy showed no evidence of harm, and bleeding problems were uncommon (USPSTF 2021).
Common questions
Can I just start baby aspirin on my own?
The recommendation is for clinicians to prescribe it to people at high risk (USPSTF 2021). Ask your doctor or midwife first, so they can check it is safe with your other medicines and conditions.
I have no risk factors. Can I still get preeclampsia?
The table only covers risk factors that can be found from your medical history (USPSTF 2021), so no ticks is not a guarantee. Keep going to your prenatal visits.
Also see the folic acid check, the blood pressure in pregnancy check, the gestational diabetes test timing, the blood pressure ranges, the BMI calculator and the screening tests by age.
Sources
- US Preventive Services Task Force. Aspirin Use to Prevent Preeclampsia and Related Morbidity and Mortality: US Preventive Services Task Force Recommendation Statement. JAMA. 2021;326(12):1186. www.uspreventiveservicestaskforce.org/uspstf/recommendation/low-dose-aspirin-use-for-the-prevention-of-morbidity-and-mortality-from-preeclampsia-preventive-medication
Written and maintained by the uncovermyrisk.com editorial team. We do not have a medical reviewer; every claim links to its primary source above. Last reviewed: 2026-10-29. Spotted an error? See About.