The Relation of Fetal Colon Diameter with Estimation of Gestational Age

Background: Conventional ultrasound dating is not very accurate after 34 weeks of gestation and has standard deviation of about 2 weeks. Objective: Verify whether fetal colon diameter can be used as a tool for estimating gestational age (GA) of fetuses between 34 to 40 weeks. Materials and Methods: This was a prospective cross-sectional study conducted at Obstetrics and Gynecology University Hospital, Damascus, Syria, during the period from September 2019-September 2020. The study enrolled 395 women with uncomplicated singleton pregnancies at 34 - 40 weeks of gestation. Fetal bi-parietal diameter, head circumference, abdominal circumference, and femoral lengths were assessed by ultrasound. In addition, descending colon diameter was assessed at the level of colonic haustra. The correlation between GA and colon diameter was assessed by the Pearson correlation test. Results: Significant correlation between fetal colon diameter and gestational age was observed P < 0.0001 (r = 0.852). In addition, a highly significant correlation between colon diameter and bi-parietal diameter, femoral length, head circumference and abdominal circumference were found with P values < 0.0001. The correlation between gestational age at 3rd trimester and colon diameter was significantly stronger than the correlation between gestational age and bi-parietal diameter, head circumference, and abdominal circumference. Whereas, no significant difference was found when comparing colon diameter and femoral lengths (P = 0.089). Conclusion: The present study suggested that colon diameter can be used for predicting third trimester gestational age.