Reproductive & Maternal Health Resource Center

Reproductive & Maternal Health Resource Center

Disclosures: The authors report no relevant financial disclosures.
January 25, 2022
2 min read

Aspirin for preeclampsia prophylaxis ‘underutilized’ for high-risk women

Disclosures: The authors report no relevant financial disclosures.
You've successfully added to your alerts. You will receive an email when new content is published.

Click Here to Manage Email Alerts

We were unable to process your request. Please try again later. If you continue to have this issue please contact

Pregnant women at highest risk for developing preeclampsia, such as those with diabetes and hypertension, are not routinely prescribed aspirin as recommended by guidelines, according to a population-based study.

In 2021, the U.S. Preventive Services Task Force recommended low-dose (81 mg) aspirin be initiated after 12 weeks’ gestation in all women at high risk for preeclampsia, as well as in women with combinations of moderate-level risk factors, Joel G. Ray, MD, MSc, FRCPC, clinician-scientist at St. Michael's Hospital in Toronto, and colleagues wrote in JAMA. Prepregnancy diabetes and chronic hypertension are common factors ranked by the USPSTF as high level and tend to cluster in women with obesity, they noted.

Graphical depiction of data presented in article
Data were derived from Ray JG, et al. JAMA. 2022;doi:10.1001/jama.2021.22749.

Large cohort studies suggest preeclampsia affects 7.3% of pregnant women with clinical risk factors and 2.7% of women without clinical risk factors.

“Low-dose aspirin, started at 12 to 20 weeks' gestation, is effective in preventing preeclampsia among women at risk, including those with prepregnancy diabetes, hypertension or obesity,” Ray told Healio. “However, our study shows that aspirin is under-utilized in these women.”

In a population-based study, researchers estimated aspirin use for preeclampsia prevention among pregnant women living in Ontario, Canada, with prepregnancy diabetes, obesity, chronic hypertension (or a combination of those factors) from April 2018 through December 2020, using data from the Better Outcomes Registry and Network Ontario. Database information includes demographics, clinical details and a yes or no field for response to the following comment: “ASA [aspirin] taken daily for preeclampsia prevention, any time after 12 weeks’ gestation.” The study period included 371,237 births.

Within the cohort, 20.9% of women had diabetes, obesity or hypertension.

Researchers found that 3.2% of pregnant women without any risk factors were prescribed aspirin (95% CI, 3.2-3.3). Among women with diabetes, the rate of aspirin use was 17.2% (95% CI, 16.2-18.2), whereas 6.9% of women with obesity (95% CI, 6.7-7.1) and 27.6% of women with hypertension (95% CI, 26.2-29) were prescribed aspirin during the first trimester.

Looking at combined risk factors, researchers found the rate of aspirin use was 22.2% (95% CI, 20.5-24) among women with diabetes and obesity, 36.6% (95% CI, 31.9-41.6) among women with diabetes and hypertension, 32.3% (95% CI, 30.2-34.5) among women with obesity and hypertension and 38.8% (95% CI, 32.9-44.9) among women with all three risk factors.

“Any practitioner — family physician, midwife, obstetrician, cardiologist, internist or endocrinologist — who is caring for a pregnant women should ask a simple question: Is this woman a candidate for low-dose aspirin for the prevention of preeclampsia?" Ray told Healio. “We need studies that can improve uptake of low-dose aspirin in women at higher risk for preeclampsia, with the interventions aimed at practitioners and the patients themselves.”

As Healio previously reported, research published in Hypertension showed high-risk pregnant women with poor adherence to aspirin therapy had higher incidence of early-onset preeclampsia, late-onset preeclampsia and preterm delivery compared with women who were adherent.

For more information:

Joel G. Ray, MD, MSc, FRCPC, can be reached at