Comparative Study of Umbilical and Cerebral Artery Flow Velocity in Normal and Foetal Growth Restriction

Background: Fetal growth restriction (FGR) is a major contributor to perinatal morbidity and mortality, frequently resulting from placental insufficiency. Doppler ultrasonography of the umbilical artery (UA) and middle cerebral artery (MCA) provides valuable insights into placental resistance and fetal adaptation. Aim: To evaluate and compare the role of umbilical and cerebral artery Doppler in pregnancies with FGR and in normal fetuses. Methods: This prospective cross-sectional study was conducted over 18 months (June 2023 – Dec 2024) in the Department of Obstetrics and Gynaecology, Adichunchanagiri Institute of Medical Sciences and Research Centre, Karnataka. Singleton pregnancies between 32–36 weeks were included. Women underwent ultrasound and color Doppler evaluation . UA and MCA pulsatility indices (PI), systolic/diastolic ratios (S/D), and cerebroplacental ratio (CPR) were measured. Estimated fetal weight was classified as appropriate for gestational age (AGA) or small for gestational age (SGA). Doppler findings were correlated with gestational age, fetal growth, and perinatal outcomes. Results: Abnormal Doppler indices were significantly more common in FGR pregnancies compared to normal pregnancies. Elevated UA PI and S/D ratio indicated increased placental resistance, while reduced MCA PI demonstrated the “brain-sparing effect.” Low CPR was strongly associated with adverse perinatal outcomes, including low birth weight, low APGAR scores, and NICU admission. In contrast, normal pregnancies exhibited progressively declining UA resistance and stable MCA PI with advancing gestation. Conclusion: Combined assessment of UA and MCA Doppler, particularly CPR, is a reliable, non-invasive tool for differentiating constitutionally small from growth-restricted fetuses. Incorporating these Doppler parameters into routine antenatal surveillance enables early detection of fetal compromise and aids in optimizing delivery timing, thereby improving perinatal outcomes.