Nearly 89% of pregnant patients were classified as being at increased risk for preeclampsia under US Preventive Services Task Force guidelines, yet only nulliparity among moderate risk factors showed meaningful predictive value, according to a recent study.

In the cohort study, researchers assessed the effectiveness of the US Preventive Services Task Force (USPSTF) guidelines in stratifying preeclampsia risk and guiding aspirin prophylaxis (AP) recommendations. The study, led by Thomas F. McElrath of the Division of Maternal-Fetal Medicine at Brigham Women’s Hospital in Boston, Massachusetts, enrolled 5684 pregnant patients across 11 US medical centers and via direct-to-participant recruitment from July 2020 to March 2023. Participants were eligible if they were 18 years or older with a singleton pregnancy that was less than 22 weeks’ gestation. Risk categorization followed USPSTF criteria, which designate high risk based on clinical conditions such as chronic hypertension and prior preeclampsia, as well as moderate risk based on nulliparity, obesity, advanced maternal age, and race.

Clinical data were abstracted from medical records and stratified by USPSTF risk category. The primary outcome was the incidence of preeclampsia. The researchers also evaluated the frequency of AP recommendation across risk strata. Of the cohort, 5046 patients (88.8%) were identified as being at increased risk of preeclampsia—70.3% were at moderate risk and 18.5% were at high risk. Preeclampsia developed in 12.1% of the cohort (685 patients) and incidence varyied by risk group: 3% in the low-risk group (19 of 638), 10.5% in the moderate risk group (419 of 3996), and 23.5% in the high-risk group (247 of 1050).

Among moderate risk factors, only nulliparity was significantly associated with increased preeclampsia risk (relative risk [RR = 1.48, 95% confidence interval [CI] = 1.35-1.62, P < .001). Advanced maternal age was inversely associated with preeclampsia (RR = 0.79, 95% CI = 0.65-0.96, P = .02), and obesity showed only marginal association (RR = 1.11, 95% CI = 1.01-1.22, P = .048). Race was not associated with elevated risk within stratified groups.

Overall, 43.1% (2438 of 5652) of participants were recommended AP. Recommendation rates differed substantially by risk group: 82% in the high-risk group, 50.4% with 2 or more moderate risk factors, 23.8% with 1 moderate risk factor, and 15.1% in the low-risk group. The authors noted that the findings suggest limited utility of moderate risk factors in guiding AP use and highlight the need for improved biologically informed risk assessment tools for preeclampsia prevention.

Full disclosures can be found in the published study.

Source: JAMA Network Open