Umbilical cord diameter and cross-sectional area in association with gestational age among women with uncomplicated pregnancies in north-central Nigeria: a cross-sectional study

Abstract

Aim and objectives: To assess gestational age using the umbilical cord diameter (UCD) and cross-sectional area (CSA). Methodology: This was a cross-sectional study among 300 women with no adverse medical history and uncom plicated pregnancies between the 14th and 40th completed weeks of pregnancy. The commonly used foetal parameters for gestational age (GA) estimation: Biparietal Diameter, Head and Abdominal Circumference and Femur Length were measured using standard protocols. UCD and CSA were measured in a plane adjacent to cord insertion into the foetal abdomen within 1 cm. UCD was measured in long axis from outer-to-outer border of the umbilical cord using the electronic calipers. The cross- sectional area was obtained in transverse axis using the ellipse measurement and area was calculated auto matically by the ultrasound machine in-built software. Measurements were taken twice for each parameter, and the average value was recorded for each participant to reduce intra-observer error. Result: The mean UCD and CSA were 16.12 ± 4.28 mm and 2.08 ± 0.87 cm respectively. UCD and CSA were observed to increase steadily with GA up to the 33rd week of gestation, decline and then remain stable from the 38th and 39th week gestation respectively until the end of pregnancy. Significant correlations (p = 0.001) be tween umbilical cord diameter and cross-sectional area with estimated foetal weight (EFW), GA and other foetal parameters for GA estimation was observed. A regression analysis model between UCD, CSA and GA showed 95% confidence interval (CI). GA by LMP (weeks) = 1.528 (UCD) + 2.646, 7.544 (CSA) + 11.540. GA by US (weeks) = 1.542 (UCD) + 2.653, 7.618 (CSA) + 11.619. Conclusion: UCD and CSA measurement is a reliable method for prediction of GA and has a strong linear rela tionship with commonly used foetal parameters.