Pregnancy outcome is largely dependent upon the successful establishment of an adequate utero-placental circulation. Defective trophoblastic invasion during early pregnancy results in increased uteroplacental vascular resistance, which can be detected by uterine artery Doppler ultrasonography1-3. During early weeks of gestation, cytotrophoblasts invade maternal spiral arteries, transforming them into low-resistance vessels which can supply sufficient blood to the growing fetus. Failure of this remodeling process results in persistent vascular resistance, placental hypoperfusion, oxidative stress and endothelial dysfunction4,5,6.

Placental-mediated disorders represent a spectrum of disease that includes preeclampsia, fetal growth restriction, oligohydramnios, placental abruption, and stillbirth. These conditions constitute to greater proportion of maternal and perinatal morbidity and mortality worldwide,8.

Uterine artery Doppler ultrasonography forms a non-invasive ,economical ,easily available method for assessing uteroplacental perfusion. Elevated pulsatility index (PI), resistance index (RI), and persistent early diastolic notching are markers of impaired placental development. The predictive value of uterine artery Doppler increases when combined with clinical risk factors and biochemical markers 6-10.

Placental abruption is a devastating complication characterized by premature separation of the placenta from the uterine wall before delivery. It is associated with severe maternal hemorrhage, disseminated intravascular coagulation, fetal distress, preterm birth and stillbirth. The underlying pathophysiology often involves abnormal placentation and impaired uteroplacental blood flow11,12.

This case series presents representative cases of placental abruption and placental insufficiency identified among women with abnormal uterine artery Doppler findings.

The cases described were identified during a prospective observational study conducted in the Department of Radiodiagnosis over a period of one year from June 2025 to May 2026 . After taking informed consent,120 singleton pregnancies in the age group of 19 to 36 years were included in our study. Multiple gestation, anomalous fetus, antenatal women already on treatment for hypertension and those who were not willing to give the consent were excluded from the study. A total of 120 pregnant women underwent first-trimester bilateral uterine artery Doppler evaluation (Pulsatility index PI) by transabdominal route on Mindray CONSONA N8 machine using curvilinear probe of frequency 1-5 Hz between 11 and 14 weeks of gestation

Among these: ● 93 women (77%) had normal Doppler findings. ● 27 women (23%) demonstrated elevated uterine artery PI in first trimester . ● 17 of the 27 women (64%) subsequently developed adverse pregnancy outcomes. Observed complications included: Complication Frequency Fetal Growth Restriction 35.2% Oligohydramnios 29.4% Preeclampsia 23.5% Placental Abruption 5.88% Stillbirth 5.88% Representative Cases Clinical Presentation A pregnant woman with an abnormal first-trimester uterine artery Doppler study was followed throughout gestation. During the third trimester, she developed clinical features suggestive of placental insufficiency and fetal growth restriction. Serial ultrasonographic examinations demonstrated abnormalities in placental morphology and fetal growth parameters. Subsequently, the patient presented with symptoms consistent with placental abruption. Imaging Findings Figure 1a-demonstrates markedly elevated uterine artery Doppler indices during first(1a) and second trimester (1b)pregnancy consistent with significant uteroplacental insufficiency and increased uteroplacental vascular resistance, suggesting a high risk for subsequent placental-mediated complications. Figure1b: The pregnant lady was followed up in the second trimester and color doppler imaging demonstrated persistent marked elevation of uterine artery Doppler indices during second trimester around 17 weeks consistent with significant uteroplacental insufficiency and increased uteroplacental vascular resistance Fig 2a Fig 2b Figures 2a and 2b: Viable intrauterine fetus with cardiac activity was documented during the same study around 17 weeks(Fig 2a). 2 week follow up Ultrasound examination of same pregnant woman presenting with pain abdomen demonstrated absent fetal cardiac activity during second trimester pregnancy after 2 weeks .This pregnancy was complicated by placental insufficiency(Fig 2b). Figure 2c. Second-trimester biometric evaluation of the same patient around 20 weeks gestational age demonstrating absent cardiac activity with reduced interval growth due to development of placental dysfunction. Figure 3a and 3b. Fetal growth restriction with reduced abdominal circumference. Third-trimester ultrasound in a pregnant lady with abnormal uterine artery doppler in first trimester demonstrates fetal abdominal circumference measuring 28.6 cm (<3rd percentile), corresponding to approximately 32 weeks and 5 days gestation. The finding is indicative of late onset fetal growth restriction secondary to placental insufficiency. Figure 4a Ultrasound image of a pregnant woman with increased uterine artery PI in first trimester presenting with pain abdomen at 30 weeks 4 days of gestational age, demonstrating large pre-placental sub-chorionic hematoma along the anterior wall of uterus. Figure 4b Ultrasound image of same pregnant woman demonstrating another pre-placental sub-chorionic hematoma along the right lateral wall and fundus of uterus . Figure 4c: Uterine artery Doppler waveform of same pregnant woman demonstrating persistent elevated uterine artery PI during the scan suggestive of increased placental vascular resistance. Figure 5a Figure 5b Figure 5a,5b : Gross specimen of placenta post delivery showing extensive placental hemorrhage and placental separation. The maternal surface of the placenta (Fig 5a)demonstrates large dark hemorrhagic areas consistent with placental abruption. The fetal surface of the placenta(Fig 5b)reveals widespread vascular congestion. Adjacent organized blood clot confirms chronic retroplacental hemorrhage secondary to placental separation.

The present case series emphasizes the clinical significance of first-trimester screening (preferably between 11 to 14 weeks)of pregnant women with uterine artery Doppler study in identifying pregnancies at risk for placental-mediated complications.

Abnormal placentation begins early in pregnancy, often before clinical symptoms appear. Inadequate trophoblastic invasion results in persistent high-resistance uterine circulation. Consequently, placental perfusion is reduced, leading to ischemia and oxidative stress2-6.

Placental abruption represents one of the most severe manifestations of placental dysfunction. Histopathological studies have consistently demonstrated vascular lesions, infarctions, decidual vasculopathy, and retroplacental hemorrhage in affected placentas.The gross pathological specimens presented in this series demonstrate extensive retroplacental clot formation, supporting the vascular origin of placental separation11,12.

Several investigators Melchiorre K et al , Kingdom JC et al and Jauniaux E et al have reported a strong association between elevated first-trimester uterine artery PI and subsequent placental complications. Increased impedance to flow reflects incomplete spiral artery remodelling and predicts the development of preeclampsia and fetal growth restriction7-10,11,12.The present cases further support this relationship.

Women with abnormal Doppler findings experienced significantly higher rates of adverse outcomes compared with those having normal Doppler studies.Fetal growth restriction was the most frequently encountered complication in our cohort. This observation aligns with the concept that placental insufficiency develops gradually and initially manifests as impaired fetal growth.

The Doppler parameters observed in these cases revealed increased vascular resistance, particularly elevated PI and RI values. These findings reflect impaired placental perfusion and support the hypothesis that abnormal placentation underlies both fetal growth restriction and placental abruption.

The major advantage of first-trimester uterine artery Doppler lies in its ability to identify high-risk pregnancies before the onset of symptoms. Early recognition permits implementation of preventive strategies such as low-dose aspirin therapy, enhanced surveillance, serial growth monitoring, and timely delivery planning6,7,8.

Placental abruption occurred less frequently but carried substantially greater maternal and fetal risk. Sonographic evidence of retroplacental hematoma and abnormal Doppler waveforms provided important clues regarding disease progression.

Despite its utility, uterine artery Doppler should not be considered a gold standard diagnostic tool. Predictive accuracy improves substantially when Doppler findings are combined with maternal history, blood pressure measurements, and biochemical markers such as placental growth factor (PlGF) and pregnancy-associated plasma protein-A (PAPP-A)4-8,13-15.

This case series demonstrates the association between abnormal first-trimester uterine artery Doppler findings and subsequent placental-mediated complications.

Placental abruption, fetal growth restriction, oligohydramnios, and preeclampsia were observed more frequently among women with increased uterine artery pulsatility indices.

The imaging findings presented illustrate the continuum of placental dysfunction and abnormal uteroplacental perfusion leading  to clinically significant placental pathology.

Routine incorporation of uterine artery Doppler into first-trimester screening protocols may help in earlier identification of high-risk pregnancies, targeted surveillance of high -risk group and improved maternal-fetal outcomes.

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