Sonographic measurement of the umbilical cord area and the diameters of its vessels during pregnancy

Abstract

The objective was to determine the cross-sectional area of the umbilical cord, its diameter and the diameter of its vessels to establish a reference curve for these parameters during pregnancy, through a prospective cross-sectional study, including 2,310 low-risk pregnancies between 12 and 40 weeks’ gestation. Means and standard deviations (SDs), plus the 10th, 50th and 90th percentiles for each measurement were calculated using polynomial regression analysis. Mann–Whitney, Kruskal–Wallis and Wilcoxon tests were used for statistical analysis. These parameters increased significantly with gestational age. The area of the cord also varied significantly with parity. Their new reference curves for low risk pregnancies were calculated using polynomial regression, and an almost linear increase in values was found up to 32 weeks of pregnancy, tending to stabilise from then onwards. The regression equation of the umbilical cord area according to gestational age (GA) was: –1.417 + 0.3026*GA–0.008*GA² + 0.000007*GA³ and the degree of adjustment (R²) was 0.89.

Keywords::

• Pregnancy
• ultrasonography
• umbilical cord
• umbilical vessels

Acknowledgement

The study was sponsored by the Department of Obstetrics and Gynaecology from the University of Campinas and by CEMICAMP (Centre for Studies in Reproductive Health of Campinas) in Brazil.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.