Study highlights gaps in preeclampsia risk assessment and aspirin use

A new study sponsored by Mirvie, which is the first to evaluate U.S. Preventive Services Task Force (USPSTF) guidelines for preeclampsia risk and aspirin prescription in a single, nationally representative, prospective population, found while high-risk factors had sufficient value in estimating risk, there's limited value for the moderate risk category - leading to nonspecific recommendations for aspirin use, a recognized prevention tool. 

This cohort study of 5684 participants, culled from the multi-center Miracle of Life prospective study, found the guidelines identified nearly 89% of pregnancies at increased risk of preeclampsia. 70.3% were in the moderate risk category, defined by maternal characteristics and broad demographics including age, body mass index, and race, while 18.5% were in the high risk category, which includes patients with conditions like chronic hypertension or prior history of preeclampsia.

The study findings suggest that the murkiness of moderate risk factors may influence clinicians' decisions regarding daily aspirin recommendations. While 82% of women with a high risk factor were recommended daily aspirin, only 37% of those with one or more moderate risk factors were given this recommendation. USPSTF, American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) all endorse guidance to consider or recommend starting aspirin between 12 to 28 weeks' gestation for pregnancies with moderate risk factors. 

"Identifying 9 out of 10 women as at risk is not helping and overburdens care teams and pregnant patients, too," said 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. "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." 

Most pregnant women in the study (70.3%) fell into the moderate risk category using the USPSTF guidelines, but having one or more moderate risk factors and no high-risk factors were not predictive of preeclampsia risk. Among individuals with 2 or more moderate risk factors but without any high risk factor, nulliparity was associated with modestly increased risk of preeclampsia (RR, 1.48; 95% CI, 1.35-1.62; P < .001); 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), and advanced maternal age (RR, 0.79; 95% CI, 0.65-0.96; P = .02).

"Rates of preeclampsia in the US have doubled in the past 15 years and continue to rise with no end in sight," said Kara Boeldt, a preeclampsia survivor and Founder and Executive Director of EndPreeclampsia.org. "The introduction of the USPSTF guidelines in 2021 didn't do anything to reverse course on the rise of preeclampsia. This important and eye-opening study highlights that we need new approaches that can predict who's truly at risk for preeclampsia, which can be so dangerous for moms and their babies. This is why I am incredibly encouraged and excited by the innovation being led by companies like Mirvie, which can finally offer some pregnant women and their care teams a clear, personalized prediction of their preeclampsia risk with a simple blood test during pregnancy."

The findings of this important study confirm the need for clear, objective measures of preeclampsia risk prediction, to motivate preventive care."

Maneesh Jain, CEO and Co-Founder, Mirvie

"With innovation like Encompass™, we can now deliver preventive care to the right patients at the right time and impact rates of preterm birth."