PREDICTIVE VALUE OF FIRST-TRIMESTER UTERINE ARTERY DOPPLER PULSATILITY INDEX FOR EARLY-ONSET PREECLAMPSIA IN A PROSPECTIVE COHORT

Dr. Aisha Khan; MD; Prof. Rajesh Patel; PhD

Abstract

Early identification of pregnant women at high risk for preeclampsia (PE) is critical for reducing maternal and neonatal morbidity. This prospective observational study evaluates the diagnostic efficacy of uterine artery Doppler (UtAD) pulsatility index (PI) measurements during the 11–13+6 week gestational window. In a cohort of 840 participants, we analyzed the correlation between first-trimester mean UtAD-PI and the subsequent development of early-onset (<34 weeks) and late-onset (≥34 weeks) preeclampsia. Statistical modeling integrated maternal characteristics with Doppler indices to establish sensitivity and specificity parameters. Findings indicate that elevated mean UtAD-PI (above the 95th percentile) serves as a potent independent predictor for early-onset PE, though its isolated predictive value for late-onset PE remains limited. The study underscores the necessity of implementing standardized Doppler ultrasound protocols in routine first-trimester screening to facilitate prophylactic interventions, such as low-dose aspirin therapy, during the optimal therapeutic window. Our results provide evidence-based support for transitioning from reactionary management to a predictive screening paradigm in obstetric care.

Keywords: Preeclampsia Prediction, Uterine Artery Doppler, First Trimester Screening, Maternal-Fetal Medicine, Pulsatility Index, Placentation, Early-onset Preeclampsia, Obstetric Ultrasound

Preeclampsia remains a leading cause of maternal and perinatal mortality globally, characterized by multisystem failure stemming from defective deep placentation. The clinical challenge lies in the fact that by the time symptoms manifest in the second or third trimester, the underlying placental pathology is often irreversible. This study addresses a critical gap in preventative obstetrics by validating non-invasive screening tools during the first trimester. Establishing the efficacy of uterine artery Doppler allows for the identification of a 'high-risk' phenotype during the critical window of trophoblastic invasion. This allows for pharmaceutical intervention (aspirin) which has been shown to reduce early-onset PE by up to 60% if started before 16 weeks. Enhancing the precision of early screening is essential for personalizing antenatal care and reducing the global burden of hypertensive disorders.

To evaluate the predictive accuracy of first-trimester uterine artery Doppler pulsatility index (PI) for the development of preeclampsia and to establish optimal cut-off values for clinical risk stratification.

A prospective cohort study was conducted involving 840 singleton pregnancies between 11+0 and 13+6 weeks of gestation at a tertiary maternal-fetal medicine unit. Maternal age, body mass index (BMI), and medical history were recorded. Transabdominal ultrasound was utilized to measure the uterine artery pulsatility index (UtAD-PI) bilaterally, with the mean PI calculated for each participant. Follow-up continued until delivery to track the occurrence of preeclampsia, defined according to ISSHP criteria. Early-onset PE was defined as delivery

95th percentile (2.35) yielded a sensitivity of 75.0% (95% CI: 42.8–94.5%) and a specificity of 94.8% (95% CI: 93.1–96.2%), with an AUC of 0.88 (p < 0.001). For late-onset PE, the sensitivity was lower at 33.3% (95% CI: 17.3–52.8%) with an AUC of 0.64 (p = 0.012). The adjusted odds ratio for developing early-onset PE in the presence of an elevated mean UtAD-PI was 12.4 (95% CI: 4.8–32.1). No significant difference was observed in mean UtAD-PI between late-onset PE and normotensive pregnancies when adjusted for maternal BMI.

The study demonstrates that first-trimester uterine artery Doppler is a highly effective tool for predicting early-onset preeclampsia, achieving high specificity and moderate sensitivity. While its performance as a standalone marker for late-onset preeclampsia is less robust, the significant correlation between impaired placentation (reflected by high UtAD-PI) and hypertensive disorders of pregnancy is undeniable. These findings advocate for the mandatory inclusion of UtAD-PI in first-trimester aneuploidy screening programs. By identifying high-risk individuals at 11–13 weeks, clinicians can initiate aspirin prophylaxis (150 mg/day) before the completion of placentation, potentially preventing the most severe forms of the disease. Future research should focus on the synergistic effect of combining UtAD with biochemical markers like PLGF to further enhance predictive performance in diverse populations.