The efficacy of different ultrasound Doppler parameters in predicting adverse fetal outcomes in pregnancies with hypertensive disorders: a systematic review and meta-analysis.

Background: Doppler ultrasound, as a noninvasive and radiation-free imaging modality, has been established as a vital diagnostic tool in contemporary obstetric practice. A meta-analysis was conducted to systematically evaluate and compare different Doppler parameters' associations with adverse fetal outcomes in pregnant women with hypertensive disorders of pregnancy (HDP) in order to identify optimal prognostic indicators for clinical decision-making. Methods: In this meta-analysis, we searched the PubMed, Embase, Cochrane Central Register of Controlled Trials (CENTRAL), China National Knowledge Infrastructure (CNKI), and Wanfang Data database, from database inception to November 13, 2024, for published and unpublished cohort studies. We included studies examining the ability of Doppler ultrasound parameters [e.g., umbilical artery pulsatility index (UA PI) and uterine artery resistance index (UtA RI)] to predict the fetal pregnancy outcomes [e.g., preterm birth and low birth weight (LBW)] of pregnant women with HDP. Two researchers independently screened the literature according to the inclusion and exclusion criteria and extracted the data. Study quality was appraised with the Newcastle-Ottawa Scale (NOS). Stata 17.0 software (StataCorp) was used to synthesize the results. The protocol was registered in the PROSPERO International Prospective Register of Systematic Reviews (registration No. CRD420250646274). Results: We included 21 references (3,692 participants) in the meta-analysis. In terms of preterm birth, the following parameters were associated with an increased risk: UA PI [odds ratio (OR) =21.60; 95% confidence interval (CI): 4.37-106.82], UA absent/reversed end-diastolic flow velocity in the umbilical artery (UA AREDF), abnormal umbilical artery half peak systolic velocity deceleration time (UA hPSV-DT), abnormal UtA RI (OR =15.26; 95% CI: 7.36-31.66), UtA PI, present uterine artery Doppler index (UtA) diastolic notch, and abnormal cerebroplacental ratio [CPR; middle cerebral artery PI (MCA-PI)/umbilical artery (UA-PI)] (OR =6.37; 95% CI: 1.54-26.33). Regarding LBW, the following parameters increased its risk: abnormal UA PI (OR =28.57; 95% CI: 8.64-94.53), UA AREDF, abnormal UA hPSV-DT, and abnormal CPR. Additionally, abnormal UA PI was associated with a significantly higher risk of LBW compared to abnormal CPR (OR =5.83; 95% CI: 1.51-22.50). The following parameters increased the risk of neonatal intensive care unit (NICU) admission: abnormal UA PI (OR =12.11; 95% CI: 3.01-48.75), abnormal UA hPSV-DT, abnormal UtA RI (OR =3.64; 95% CI: 1.18-11.24), and abnormal CPR (OR =5.86; 95% CI: 2.71-12.68). The following parameters increased the risk of fetal growth restriction (FGR): UA AREDF (OR =2.73; 95% CI: 1.26-5.91), abnormal UtA RI/present UtA diastolic notch (OR =8.79; 95% CI: 5.22-14.80), abnormal UtA PI, and abnormal CPR. Furthermore, compared to UA AREDF, both abnormal UtA RI/presence of a diastolic notch (OR =3.22; 95% CI: 1.27-8.19) and abnormal UtA PI (OR =3.08, 95% CI: 1.19-7.97) were associated with a higher risk of FGR. Conclusions: In patients with HDP, abnormal UA PI, and CPR are risk factors for multiple adverse fetal outcomes. Additionally, for LBW, abnormal UA PI is associated with a higher risk than is abnormal CPR, while for FGR, abnormal UtA RI/presence of a uterine artery diastolic notch and abnormal UtA PI are associated with higher risks than are UA AREDF.