# The correlation of umbilical cord blood quality and placental function with neonatal outcomes in fetal growth restriction

## TL;DR

This study finds that placental function and umbilical cord blood quality are linked to neonatal outcomes in pregnancies with fetal growth restriction.

## Contribution

The study identifies specific umbilical artery Doppler and cord blood parameters as novel predictors of neonatal prognosis in fetal growth restriction.

## Key findings

- Elevated umbilical artery pulsatility index (PI), resistance index (RI), and systolic/diastolic (S/D) ratio are associated with unfavorable neonatal outcomes.
- Impaired acid-base balance in umbilical cord blood, indicated by lower pH and pO2, correlates with poor neonatal prognosis.
- Placental function indices and cord blood gas analysis provide significant predictive value when adjusted for gestational age and birth weight.

## Abstract

Fetal growth restriction (FGR) poses significant risks to neonatal health, necessitating reliable prognostic indicators. This study evaluates predictive factors including umbilical cord blood parameters, placental function indices, and umbilical artery Doppler measurements for neonatal outcomes in FGR.

This retrospective cohort study analyzed clinical records of 412 pregnant women with FGR admitted from January 2022 to December 2023. Participants were divided into favorable prognosis (5-min Apgar score >7; n = 310) and unfavorable prognosis (5-min Apgar score ≤7, fetal demise, intrauterine fetal death, or neonatal death; n = 102) groups. Data included demographic details, hematological and coagulation parameters, ultrasound findings, and umbilical cord blood gas analysis. Variance inflation factor (VIF) testing was performed to assess multicollinearity, and potential confounders including gestational age, birth weight, and neonatal sex were incorporated into multivariate analysis.

The unfavorable prognosis group demonstrated earlier gestational age at diagnosis (p = 0.028) and birth (p = 0.008), lower birth weight (p = 0.003), and lower 5-min Apgar scores (p < 0.001). Routine blood and coagulation parameters showed no significant differences between groups. Placental function indices (Flow Index, Vascularization Index, Vascularization Flow Index) were significantly higher in the favorable group (all p < 0.05). Umbilical artery Doppler parameters including pulsatility index (PI), resistance index (RI), and systolic/diastolic (S/D) ratio were significantly lower in the favorable group (all p < 0.05). Umbilical cord blood analysis revealed higher pH (p = 0.004), pO2 (p = 0.014), and HCO3− (p = 0.010), with lower pCO2 (p = 0.009) in the favorable group. Multicollinearity testing revealed acceptable VIF values (<5) for all predictors. Multivariate logistic regression, adjusted for gestational age, birth weight, and sex, identified elevated PI (OR = 3.421, 95% CI: 1.284–9.112), RI (OR = 18.652, 95% CI: 3.012–115.478), S/D ratio (OR = 1.498, 95% CI: 1.168–1.922), and pCO2 (OR = 1.046, 95% CI: 1.016–1.077), along with decreased pH (OR = 0.001, 95% CI: 0.000–0.028), pO2 (OR = 0.908, 95% CI: 0.831–0.992), and HCO3− (OR = 0.904, 95% CI: 0.824–0.992) as significant predictors. The model achieved an AUC of 0.795 (sensitivity 0.686, specificity 0.781), with the Hosmer–Lemeshow test indicating adequate calibration (χ2 = 8.42, p = 0.394).

Elevated umbilical artery PI, RI, and S/D ratio, combined with impaired acid–base balance, are associated with unfavorable neonatal prognosis in FGR. These findings emphasize the importance of comprehensive monitoring of placental function and umbilical cord blood parameters in FGR-affected pregnancies.