Gestational Age - Wise Morphometric Analysis of the Human Foetal Large Intestine: A Cross - Sectional Cadaveric Study

Background: Gestational age wise morphometric data for the human foetal large intestine remain limited, despite the clinical importance of these measurements in the interpretation of congenital intestinal disorders and prenatal imaging. Material and Methods: This observational cross - sectional study was conducted in the Department of Anatomy, Motilal Nehru Medical College, Prayagraj. Fifty-one human foetal specimens were included. Foetuses were grouped into 15–20 weeks (n=8), 21–25 weeks (n=10), 26–30 weeks (n=16), 31–35 weeks (n=7), and 36–40 weeks (n=10). Full colonic length and segmental transverse, anteroposterior, and average diameters from the caecum to the sigmoid colon were measured and correlated with crown-rump length (CRL), abdominal circumference (AC), and head circumference (HC). Results: Mean gestational age was 27.94 ± 6.198 weeks. Mean full colonic length was 20.82 ± 3.88 cm and increased from 18.63 ± 3.249 cm at 15–20 weeks to 26.60 ± 1.838 cm at 36–40 weeks. All transverse diameters increased significantly with gestational age, and the sigmoid colon showed the highest mean transverse diameter (5.18 ± 1.76 mm). Anteroposterior diameters also increased significantly in all segments except the sigmoid colon (p = 0.167). Average diameters increased significantly across all segments, with the sigmoid colon again showing the highest mean value (4.29 ± 1.41 mm). All foetal morphometric parameters showed positive significant correlations with colonic measurements; the strongest correlation between CRL and transverse diameter was observed in the sigmoid colon (r = 0.613, p < 0.001). Conclusion: The human foetal large intestine shows progressive morphometric enlargement with advancing gestation. Colonic length and segmental diameters increase significantly, and the sigmoid colon emerges as the largest and most dynamic segment. These findings provide baseline morphometric reference data for anatomical, radiological, and paediatric surgical applications.

Keywords: Foetal large intestine, morphometry, colon, caecum, sigmoid colon, gestational age.