Fetal Outcomes and Prevalence of Abnormal Umbilical Artery Doppler Ultrasound among Pregnant Women Diagnosed with Pregnancy Induced Hypertension at Moshi Municipal, Tanzania

Abstract

Background: Pregnancy-Induced Hypertension (PIH) is characterized by new-onset elevated blood pressure (systolic ≥140 mmHg or diastolic ≥90 mmHg) after 20 weeks of gestation, with or without proteinuria. PIH may progress to preeclampsia, leading to placental insufficiency and adverse fetal outcomes. Umbilical artery Doppler ultrasound is a non-invasive tool that reflects placental vascular resistance and can predict adverse fetal outcome. Objective: To investigate fetal outcomes, prevalence and maternal factors associated with abnormal umbilical artery Doppler findings among pregnant women diagnosed with PIH. Methods: This was a hospital-based prospective cohort study enrolled 136 pregnant women diagnosed with PIH at Moshi Municipal hospitals between August 2024 and May 2025. Participants underwent obstetric ultrasound and umbilical artery Doppler assessment, including resistive index (RI), Pulsatility index (PI), and systolic/diastolic (S/D) ratio. Fetal biometric parameters were evaluated, and 116 participants were followed up to one month postpartum to assess fetal outcomes. Logistic regression was used to identify maternal factors associated with abnormal Doppler findings dysfunction caused by obliteration of small arteries within the chorionic villi, ultimately leading to both fetal and maternal compromise. Results: The prevalence of abnormal umbilical artery Doppler ultrasound findings was 47.42%. Absent end-diastolic flow (AEDF) was observed in 11.2% of participants, while 38.8% had elevated resistive indices. Adverse fetal outcomes included low birth weight (22.4%), severe birth asphyxia (6.1%), stillbirth (6.0%), and preterm delivery (32.8%). Moderate systolic hypertension (AOR = 1.572; P= 0.047; CI: 0.119–2.754) and severe systolic hypertension (AOR = 1.759; P = 0.034; CI: 0.167–3.452) were significantly associated with abnormal Doppler findings. Similarly, moderate diastolic hypertension (AOR = 1.627; p = 0.038; CI: 0.159–2.467) and severe diastolic hypertension (AOR = 1.909; P = 0.021; CI: 0.08–2.890) showed significant associations. Conclusion: Nearly half of the participants had abnormal umbilical artery Doppler findings, which were strongly associated with adverse fetal outcomes, including preterm delivery and low birth weight. Elevated maternal blood pressure, particularly diastolic hypertension, significantly increased the likelihood of abnormal Doppler indices. Umbilical artery Doppler ultrasound is an important predictor of fetal compromise in pregnancies complicated by PIH.