Umbilical Coiling Index, Doppler Parameters, and Cord Blood Gas Analysis: Lack of Correlation in Uncomplicated Term Pregnancies

TL;DR

This study found no link between fetal umbilical coiling and blood gas levels in healthy term pregnancies, suggesting the coiling index may not predict neonatal acidosis.

Contribution

The study demonstrates that umbilical coiling index lacks correlation with fetal well-being markers in low-risk term pregnancies.

Findings

Umbilical coiling index (UCI) showed no significant correlation with cord blood gas values, IMA, or Doppler indices.

Umbilical venous pH was positively correlated with 5-minute Apgar scores, while pCO2 was negatively correlated.

NICU admissions were associated with higher UA Doppler indices and lower venous pH.

Abstract

Background/Objectives: In this study, we aimed to evaluate whether neonatal ischemia-modified albumin (IMA) and umbilical venous cord blood gas parameters are associated with antenatal markers of fetal well-being, including the umbilical coiling index (UCI) and umbilical artery (UA) and middle cerebral artery (MCA) Doppler indices. Methods: For this prospective observational study, sixty-five low-risk term pregnancies (≥37 weeks) were included. Prenatal ultrasound was used to measure the UCI and UA/MCA Doppler indices. At delivery, umbilical venous cord blood gas and serum IMA analyses were performed. Maternal and neonatal data (birth weight, 5 min Apgar score, NICU admission, sex, and delivery mode) were recorded, and correlations and group comparisons were performed (p < 0.05). Results: The UCI ranged from 0.210 to 0.471 coil/cm (mean 0.337). The UA and MCA Doppler indices were within the reference ranges. The UCI showed no significant correlation with umbilical venous blood gas values, IMA, UA/MCA Doppler indices, gestational age/weeks, or 5 min Apgar score. The UA S/D ratio and UA resistive index (RI) were negatively correlated with birth weight (p < 0.05). Umbilical venous pH was positively correlated with the 5 min Apgar score, whereas venous pCO2 was negatively correlated with the 5 min Apgar score (both p < 0.05). Newborns with venous pH < 7.32 had higher cesarean delivery rates and higher rooming-in rates. Newborns admitted to the NICU had higher mean UA systolic velocity/diastolic velocity (S/D) and UA pulsatility index (PI) and lower venous pH. Conclusions: In low-risk term pregnancies, the UCI was not associated with cord blood gas parameters, IMA, or UA/MCA Doppler indices. These results suggest that the UCI may have limited clinical utility as a predictor of early neonatal acidosis or oxidative stress in a strictly low-risk population.

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