Ultrasound measurement of umbilical vein diameter in normal pregnancy and correlation with gestational age and fetal weight

Background: With the invention of more sophisticated ultrasonography techniques, there is room to explore and better comprehend the link between gestational age (GA), fetal weight (FW), and the diameter of the umbilical vein (UV). Aim: To explore the relationship between umbilical vein diameter (UVD) and GA as well as FW in normal pregnancy. Materials and Methods: This descriptive, cross-sectional study was conducted between February and August 2022 at the obstetric units and radiology departments of two tertiary health facilities: one secondary facility and one radiodiagnostic facility in the state. A transabdominal ultrasound scan was used to assess the UV. The relationship between UVD and GA and between UVD and estimated fetal weight (EFW) was explored using Pearson's correlation analysis. A nomogram was constructed, and the level of significance was set at P < 0.05. Results: There was a very strong, positive and significant relationship between UVD and GA (r =0.63; P = 0.001) and between UVD and EFW (r = 0.57; P = 0.001). For every unit change in GA, there was a 39% change in UVD (r2 = 0.39), while every unit change in FW was associated with a corresponding 33% change in UVD (r2 = 0.33). The regression coefficients for GA were 0.257 (β0) and 0.015 (β1), while β0 and β1 for FW were 0.590 and 0.069, respectively. Conclusion: Our study revealed a very strong, positive and significant relationship between UVD and GA and between UVD and EFW.