# Sonographic Association of Umbilical Cord Thickness in the Third Trimester of Pregnancy With Fetal Outcome in a Rural Indian Population

## TL;DR

Thinner umbilical cords in late pregnancy are linked to lower birth weight and other poor outcomes in rural India.

## Contribution

This study identifies umbilical cord thickness in the third trimester as a potential predictor of adverse neonatal outcomes in a rural Indian population.

## Key findings

- Lean umbilical cords were significantly associated with low birth weight, NICU admission, meconium-stained liquor, and low APGAR scores.
- Maternal BMI was positively correlated with umbilical cord thickness.
- Thick cords were less common but not associated with increased adverse outcomes compared to normal cords.

## Abstract

Objectives

To assess the association between third-trimester umbilical cord thickness measured on ultrasonography and key neonatal outcomes (birth weight, NICU admission, APGAR score, and meconium-stained liquor) and to examine the association between umbilical cord thickness and selected maternal characteristics, including body mass index.

Design

This is a prospective observational study conducted over 24 months.

Material and methods

A total of 126 antenatal women with singleton pregnancies between 32 and 40 weeks of gestation with normal amniotic fluid index (8-24 cm) and three vessel unit umbilical cord attending a rural tertiary care hospital were enrolled. Exclusion criteria included medical comorbidities affecting fetal outcomes such as gestational diabetes, hypertensive disorders, anemia, maternal chronic illnesses, and fetal congenital anomalies; fetal growth restriction, prematurity, and prelabour rupture of membranes. Umbilical cord thickness was measured sonographically at a free-floating loop approximately one cm from placental insertion using a five MHz curvilinear probe. Measurements were taken thrice and averaged for accuracy. The cord parameters were classified into lean (<10th percentile), normal (10th-90th percentile), and thick (>90th percentile) groups based on study percentiles. Fetal outcomes measured at delivery included birth weight (with low birth weight defined as <2.5 kg), APGAR scores at five minutes (with less than 7 considered low), presence of meconium-stained liquor, and NICU admissions. Statistical correlations were assessed using chi-square tests and Pearson/Spearman correlation coefficients, with p-values <0.05 considered significant.

Results

Among participants, 19(15%) had lean cord thickness, 89 (70.7%) had a normal cord, and 18 (14.3%) had a thick cord. Lean cords showed a significant association with adverse outcomes: 14 (73.6%) neonates with lean cords had low birth weight compared with 10 (11.2%) in the normal group. NICU admission rates were higher in the lean group (11, 57.8%) than in the normal (6, 6.8%) and thick cord (2, 11.2%) groups. Meconium-stained liquor was present in seven (36.9%) of lean cords versus five (5.7%) in normal cords. Low APGAR scores (<7 at five minutes) were significantly more frequent in lean cords. Maternal body mass index was positively correlated with umbilical cord thickness (p=0.0006).