Aspirin for Preeclampsia Prevention Shows Low Rates Despite USPSTF Recommendations

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Rates of aspirin use for preeclampsia prophylaxis were observed in a minority of women with risk factors including pre-pregnancy diabetes, obesity, or chronic hypertension.

Although the US Preventive Services Task Force (USPSTF) recommended low-dose aspirin for women at high risk for preeclampsia, low rates (7.6%) of aspirin use in eligible patients have been observed, despite a relative risk reduction of 10% - 50% against preeclampsia.

Thus, a recent study estimated aspirin use for preeclampsia prevention in pregnant women with moderate-level risk factors, including pre-pregnancy diabetes, obesity, chronic hypertension, and a combination of these factors.

Lead investigator Joel G. Ray, MD, Department of Medicine, St Michael’s Hospital and colleagues observed aspirin was used for preeclampsia prophylaxis in a minority of women with these risk factors or a combination of all three.


Women from Ontario, Canada with a hospital live birth or stillbirth at 23 weeks’ gestation or greater from April 2018 - December 2020 were included in the study. The data were obtained from the Better Outcomes Registry (BORN).

In BORN, all hospitalized birth data were collected by health care professionals from charts, clinical forms, and patient interviews and entered into the system. It included demographics, clinical details, and a yes or no answer for “aspirin taken daily for preeclampsia prevention, any time after 12 weeks’ gestation.”

Rates of aspirin use overall and those with diabetes, obesity, or hypertension were calculated using 95% confidence intervals.


A total of 371,237 births were included during the study period. Pregnant women with diabetes, obesity, or hypertension were older, had a higher body mass index, more preterm birth, and a longer hospital length of stay, in contrast to those without any of the conditions.

Moreover, women with diabetes, obesity, or hypertension (n = 77,582) comprised 20.9% of the sample population. Aspirin was used by 3.2% (95% CI, 3.2% - 3.3%) of women without diabetes, obesity, or hypertension.

Data show the rate of aspirin use was 17.2% (95% CI, 16.2% - 18.2%) in women with diabetes, 6.9% (95% CI, 6.7% - 7.1%) in women with obesity, and 27.6% (95% CI, 26.2% - 29.0%) in women with hypertension.

Further, the numbers on aspirin use was 22.2% (95% CI, 20.5% - 24.0%) in women with diabetes and obesity, 36.6% (95% CI, 31.9% - 41.6%) in women with diabetes and hypertension, and 32.3% (95% CI, 30.2% - 34.5%) in women with obesity and hypertension. The rate was 38.8% (95% CI, 32.9% - 44.9%) in women with all 3 factors.


“For the 2021 USPSTF recommendations to be more influential, more data are needed to characterize barriers for aspirin adoption among suitable women at the patient and practitioner level, and additional knowledge translation initiatives developed,” Ray and colleagues concluded.

The research letter, “Aspirin Use for Preeclampsia Prevention Among Women With Prepregnancy Diabetes, Obesity, and Hypertension,” was published in JAMA.