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2025
New study in JAMA Network Open shows current guidelines and approaches to assessing preeclampsia risk are failing the majority of pregnant moms, resulting in ineffective preventive care
A new study published in JAMA Network Open is first to evaluate the U.S. Preventive Services Task Force (USPSTF) guidelines for preeclampsia risk and aspirin prescription in a single, nationally representative, prospective population. The study, which included 5,684 participants, found that current guidelines relying on maternal characteristics and broad demographics identify 89% of pregnancies as having an increased risk of preeclampsia.
JAMA Fig. A
JAMA Fig. B
In this prospective cohort study of singleton pregnancies, 89% of the population was at increased risk of preeclampsia (either moderate or high) by USPSTF criteria. Aspirin recommendations were effectively implemented only for high and low risk categories. Moderate risk factors, in the absence of high risk factors, had little or no value for estimating the risk of developing preeclampsia, leading to nonspecific recommendation of aspirin prophylaxis in the moderate risk category.
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FINDINGS:
Current moderate-risk categorization is failing pregnant moms: 
  • 70.3% of participants were placed in the moderate risk category, defined by maternal characteristics and broad demographics including age, body mass index, and race
  • 18.5% were placed in the high-risk category, which includes patients with pre-existing conditions like chronic hypertension, diabetes, and personal history of preeclampsia
Aspirin under recommended:
  • Only 37% of those in the moderate risk category were recommended daily aspirin despite USPSTF, American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine all endorsing guidance to consider or recommend starting aspirin between 12 to 28 weeks’ gestation for pregnancies with moderate risk factors
  • 82% of women in the high-risk category were recommended daily aspirin in the study
Little or no predictive value of moderate risk factors:
  • Having one or more moderate risk factors (without high-risk factors) was a poor predictor of preeclampsia risk 
  • Specifically, among individuals with two or more moderate risk factors but no high-risk factors:
    • Nulliparity was associated with modestly increased risk of preeclampsia (RR, 1.48; 95% CI, 1.35-1.62; P < .001)
    • But there was little or no association with:
      • Obesity (RR, 1.11; 95% CI, 1.01-1.22; P = .048)
      • Black race (RR, 0.95; 95% CI, 0.80-1.14; P = .63)
      • Advanced maternal age (RR, 0.79; 95% CI, 0.65-0.96; P = .02)
“Identifying 9 out of 10 women as at risk is not helping and overburdens care teams and pregnant patients, too. Physicians may be reluctant to prescribe aspirin when the majority of their patients fall into the moderate risk category. This is compounded by less than 25% compliance with aspirin use by patients in the moderate risk category.”
— Dr. Thomas McElrath
Vice President of Clinical Development at Mirvie and a practicing maternal-fetal medicine physician at Mass General Brigham, as well as lead author of the study.
CLINICAL SIGNIFICANCE:
  • Rates of preeclampsia in the US have doubled in the past 15 years, but the introduction of USPSTF guidelines in 2021 has not helped reverse the rise of preeclampsia
  • Current preeclampsia risk assessment guidelines may lead to ineffective preventive care due to their non-specific nature
  • The limited predictive value of moderate risk factors, coupled with low aspirin prescription rates and poor patient compliance in this group, indicates a need for more precise risk-stratification tools
  • Innovations like Encompass™ can deliver clear, objective measures of preeclampsia risk prediction, to motivate preventive care
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