Correlation of Doppler indices and umbilical coiling with birthweight and small gestational age prediction in term pregnancies

ObjectivesThis study aims to investigate the correlation of Doppler ultrasound indices of umbilical artery (UA), middle cerebral artery (MCA), cerebro-placental ratio (CPR), length of umbilical cord (UC) coiling, and birthweight, as well as the predictors of these parameters for small for gestational age (SGA).MethodsThis cross-sectional study was conducted between June 2022 and June 2024 at Hue University of Medicine and Pharmacy Hospital, Vietnam. The study enrolled 337 full-term primigravida with uncomplicated singleton pregnancies who underwent Doppler transabdominal ultrasound between 37⁺⁰ and 41⁺⁰ weeks of gestation to assess fetal Doppler indices and length of UC coiling. Birthweight was collected at delivery.ResultsThe study found significant differences relating birthweight and resistance index of umbilical artery (RI-UA) between abnormal and normal coiling groups (3028.83 ± 469.81 vs 3129.52 ± 378.82 and 0.604 ± 0.087 vs 0.579 ± 0.073). There was a significantly weak negative correlation between RI of umbilical artery Doppler and birth weight (r = -0.178). Additionally, a significantly weak positive correlation coefficient between CPR and birth weight (r = 0.111) was found. Length of umbilical cord coiling had a weak positive correlation with pulsatility index of uterine artery (PI-UA). RI of umbilical artery Doppler helps in predicting the small gestational age at birth with AUC: 0.72 (0.57-0.87).ConclusionRI-UA and birthweight were significantly different between abnormal and normal coiling pregnancies. The higher RI-UA is more related to lower birthweight. RI-UA helps in predicting the small gestational age at birth better than other parameters.