Mid-Trimester Uterine Artery Doppler for Aspirin Discontinuation in Pregnancies at High Risk for Preterm Preeclampsia: Post Hoc Analysis of StopPRE Trial

Abstract

(BJOG. 2024;131(3):334–342. doi: 10.1111/1471-0528.17631) Preeclampsia (PEC) is characterized by hypertension and proteinuria or organ dysfunction after 20 weeks of gestation. The cause of the condition has not been fully elucidated; however, PEC is associated with a defect in the development of the placenta in early-onset patients. In unaffected individuals, uterine artery flow impedance (UtA) decreases during early gestation through week 24. However, if pulsatility index (PI) in UtA remains high, it is a sign of maladaptation and is commonly found in patients with preterm PEC. An additional consequence of impaired placentation is uteroplacental ischemia, during which the levels of placental growth factor (PIGF) are decreased and soluble fms-like tyrosine kinase-1 (sFlt-1) increases. In screening first trimester patients for risk of PEC, UtAPI and PIGF may be used. Clinicians prescribe aspirin daily as a preventative measure in patients who screen at risk for PEC. Although the incidence of PEC greatly decreases with this treatment, it is also noteworthy that screening for risk of PEC during the first trimester results in a high false positive rate. Thus, most women pre-emptively receiving aspirin for PEC are false positives. The authors previously performed a study where aspirin was discontinued in patients between 24 and 28 weeks of gestation with a normal sFlt-1/PlGF ratio of ≤38, identifying false positives cases. Although this study showed promising results, the ratio may not be available for use in every clinic. Thus, in this study, the authors examine whether UtAPI can be a correlate for these angiogenic factors and act as an alternative screening measure at 24 to 28 weeks of gestation with the same purpose to discontinue aspirin and assess incidence of preterm PEC.