European Journal of Cardiovascular Medicine

Placental insufficiency is a significant complication in high-risk pregnancies, associated with increased perinatal morbidity and mortality¹. It is characterized by inadequate placental function, leading to reduced fetal oxygenation and nutrition. Early detection and appropriate management of placental insufficiency are crucial for improving maternal and fetal outcomes^2,3.

In recent years, Doppler ultrasound has emerged as a valuable non-invasive tool for assessing fetal well-being and placental function⁴. This technique allows for the evaluation of blood flow in various fetal and maternal vessels, providing important information about placental perfusion and fetal hemodynamics⁵.

The umbilical artery (UA) Doppler is widely used to assess placental resistance and fetal well-being. Abnormal UA Doppler findings, such as absent or reversed end-diastolic flow, are associated with poor perinatal outcomes⁶. The middle cerebral artery (MCA) Doppler helps in detecting fetal hypoxia and anemia, while uterine artery (UtA) Doppler can predict the risk of pre-eclampsia and fetal growth restriction⁷.

Despite the growing use of Doppler ultrasound in obstetric practice, there is a need for more comprehensive studies evaluating its role in diverse high-risk populations. Furthermore, the impact of Doppler findings on clinical decision-making and pregnancy management requires further investigation.

This study aims to evaluate the effectiveness of Doppler ultrasound in assessing placental insufficiency and predicting adverse outcomes in high-risk pregnancies. Additionally, we seek to examine how Doppler findings influence management decisions in clinical practice. By conducting this research in Kolkata, West Bengal, we also aim to contribute to the understanding of Doppler ultrasound utility in the context of a developing country's healthcare system.

Study Design and Setting: This observational study was conducted at Medical College and Hospital, Kolkata, West Bengal, India, from March 2019 to February 2020.

Study Population: We enrolled 100 pregnant women with high-risk pregnancies attending the antenatal clinic or admitted to the obstetrics ward. High-risk factors included chronic hypertension, gestational diabetes, previous history of intrauterine growth restriction (IUGR), pre-eclampsia, multiple gestation, and other risk factors as determined by the attending obstetrician.

Inclusion Criteria:

Singleton or multiple pregnancies

Gestational age between 28 and 40 weeks

Presence of one or more high-risk factors

Exclusion Criteria:

Known fetal chromosomal or structural anomalies

Inability to provide informed consent

Data Collection: Demographic data and obstetric history were collected using a standardized questionnaire. Gestational age was determined based on the last menstrual period and confirmed by first-trimester ultrasound.

Doppler Ultrasound Examination: All participants underwent Doppler ultrasound examinations performed by experienced sonographers using a 3.5-5 MHz curvilinear transducer. The following vessels were evaluated:

1. Umbilical artery (UA)
2. Middle cerebral artery (MCA)
3. Uterine arteries (UtA)

Doppler indices including the Pulsatility Index (PI), Resistance Index (RI), and Systolic/Diastolic (S/D) ratio were measured. Abnormal Doppler findings were defined according to established reference ranges for gestational age.

FIG 1: Umbilical artery Doppler images. Fig A: UA Doppler study with PI>90 centile at 30 weeks POG. Fig B: UA AEDF (absent end diastolic flow). Fig C: UA REDF (reverse end diastolic flow)

Follow-up and Outcome Assessment: Participants were followed until delivery. Pregnancy outcomes including gestational age at delivery, birth weight, mode of delivery, NICU admission, and perinatal complications were recorded. Placental insufficiency was confirmed by histopathological examination of the placenta when clinically indicated.

Management Changes: Any changes in pregnancy management based on Doppler findings, such as increased fetal monitoring, antenatal corticosteroid administration, or decision for early delivery, were documented.

Statistical Analysis: Data were analyzed using SPSS Software. Descriptive statistics were used for demographic data and Doppler findings. The diagnostic accuracy of UA Doppler for placental insufficiency was assessed by calculating sensitivity, specificity, positive predictive value, and negative predictive value. The association between abnormal Doppler findings and adverse outcomes was evaluated using odds ratios with 95% confidence intervals. A p-value <0.05 was considered statistically significant.

Ethical Considerations

This study was approved by the Institutional Ethics Committee. Written informed consent was obtained from all participants after thorough explanation of the study procedures. Patient confidentiality was maintained throughout the study, with all data anonymized during analysis and reporting. The study design ensured that all participants received standard care, with Doppler ultrasound examinations not interfering with routine clinical management.

Our observational study included 100 high-risk pregnancies with a mean maternal age of 29.3 ± 5.2 years. The mean gestational age at examination was 32.1 ± 3.7 weeks (Table 1).

The most common high-risk factors were chronic hypertension (22%), gestational diabetes (18%), and previous history of intrauterine growth restriction (15%). Pre-eclampsia was present in 12% of cases, while 8% were multiple gestations. Other risk factors accounted for 25% of the cohort (Table 2).

Doppler ultrasound revealed abnormal findings in 35% of umbilical artery (UA) examinations, 28% of middle cerebral artery (MCA) examinations, and 32% of uterine artery (UtA) examinations (Table 3).

The correlation of abnormal UA Doppler with placental insufficiency showed high diagnostic accuracy. The sensitivity was 82.5% (33/40 cases of confirmed placental insufficiency), and specificity was 96.7% (58/60 cases without placental insufficiency). The positive predictive value was 94.3% (33/35), and the negative predictive value was 89.2% (58/65) (Table 4).

Regarding pregnancy outcomes, 38% of the cohort experienced preterm delivery (<37 weeks), 32% had low birth weight infants (<2500g), and 28% required NICU admission. The stillbirth rate was 2% (Table 5).

We observed significant correlations between abnormal Doppler findings and adverse outcomes. Abnormal UA Doppler was associated with increased odds of preterm delivery (OR 3.8, 95% CI: 2.1-6.9). Abnormal MCA Doppler correlated with increased risk of low birth weight (OR 2.9, 95% CI: 1.7-5.2), while abnormal UtA Doppler was associated with higher odds of pre-eclampsia (OR 4.2, 95% CI: 2.3-7.6) (Table 6).

The mean time from detection of abnormal Doppler findings to delivery was 2.8 ± 1.9 weeks (Table 7).

Doppler findings influenced management decisions in a substantial proportion of cases. Increased fetal monitoring was implemented in 45% of pregnancies, antenatal corticosteroids were administered in 30%, and early delivery was indicated in 22% of cases (Table 8).

Table 1: Demographics

Table 2: High-risk pregnancy factors

Table 3: Doppler ultrasound findings

Table 4: Correlation of abnormal UA Doppler with placental insufficiency

Table 5: Pregnancy outcomes

Table 6: Correlation between Doppler findings and adverse outcomes

Table 7: Time from abnormal Doppler findings to delivery

Table 8: Management changes based on Doppler findings

FIG 2: Doppler Ultrasound Findings

FIG 3: Correlation of Abnormal UA Doppler with Placental Insufficiency

FIG 4: Management Changes Based on Doppler Findings

This observational study demonstrates the significant role of Doppler ultrasound in assessing placental insufficiency and predicting adverse outcomes in high-risk pregnancies. Our findings highlight the clinical utility of this non-invasive technique in guiding management decisions and potentially improving perinatal outcomes.

The high sensitivity (82.5%) and specificity (96.7%) of umbilical artery (UA) Doppler for detecting placental insufficiency underscore its value as a screening tool. This aligns with previous studies, such as Alfirevic et al. (2017), who reported similar diagnostic accuracy in a systematic review. The strong positive predictive value (94.3%) suggests that abnormal UA Doppler findings should prompt careful monitoring and potential intervention.

Our results showed significant associations between abnormal Doppler findings and adverse outcomes. The increased odds of preterm delivery with abnormal UA Doppler (OR 3.8, 95% CI: 2.1-6.9) are consistent with findings by Yılmaz C et al⁸, who reported similar correlations in growth-restricted fetuses. The association between abnormal middle cerebral artery (MCA) Doppler and low birth weight (OR 2.9, 95% CI: 1.7-5.2) supports its role in identifying fetuses at risk of growth restriction, as previously described by Kumar A et al⁹.

FIG 5: MCA Doppler study images at 30 weeks POG in (A) PIH and (B) Normal patient showing a relative brain sparing effect in PIH patient.

The correlation between abnormal uterine artery (UtA) Doppler and pre-eclampsia (OR 4.2, 95% CI: 2.3-7.6) reinforces its potential as a predictive tool for this condition. This finding is in line with a meta-analysis by Rane BM et al¹⁰, which demonstrated the predictive value of UtA Doppler for pre-eclampsia in high-risk pregnancies.

FIG 6: Uterine artery Doppler study at 30weeks POG in a patient with chronic hypertension, APLA and bad obstetric history being managed with thromboprophylaxis and ecosprin 150mg from 1^st trimester itself.

Importantly, our study reveals the impact of Doppler findings on clinical management. The high rate of management changes (45% of cases) based on Doppler results, including increased fetal monitoring, antenatal corticosteroid administration, and early delivery, demonstrates its influence on clinical decision-making^11,12. This is particularly relevant in resource-limited settings like Kolkata, where judicious use of interventions is crucial.

The mean time of 2.8 ± 1.9 weeks from abnormal Doppler findings to delivery suggests a window of opportunity for interventions aimed at improving fetal outcomes. This timeframe allows for important interventions such as antenatal corticosteroid administration, which was implemented in 30% of our cases¹³.

Despite these encouraging findings, our study has limitations. The relatively small sample size and single-center design may limit the generalizability of our results. Additionally, the observational nature of the study precludes definitive conclusions about the causal relationship between Doppler findings and outcomes¹⁴.

Future research should focus on larger, multicenter studies to validate these findings across diverse populations. Randomized controlled trials evaluating the impact of Doppler-guided management on perinatal outcomes would provide stronger evidence for its clinical application. Furthermore, cost-effectiveness analyses would be valuable in determining the optimal integration of Doppler ultrasound in antenatal care protocols, particularly in resource-constrained settings.

Our study demonstrates that Doppler ultrasound is a valuable tool for assessing placental insufficiency and predicting adverse outcomes in high-risk pregnancies. Its influence on clinical management decisions underscores its potential to improve perinatal care. As we continue to refine our understanding of its applications, Doppler ultrasound may play an increasingly crucial role in optimizing outcomes for high-risk pregnancies in both developed and developing healthcare settings.

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2. Kale RM, Tirupathi RG, Sheela SR. Role of Ultrasonography and Color Doppler in the Assessment of High-Risk Pregnancies and Their Accuracy in Predicting Fetal Outcome. Cureus. 2023 May 15;15(5):e39017. doi: 10.7759/cureus.39017. PMID: 37323339; PMCID: PMC10265127.
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