Doppler impedance changes at the fetal brain vessels in a pregnancy affected with a multiple combination of uteroplacental anomalies

Comparison of Cerebroplacental Ratio, Intergrowth-21st Standards, Customized Growth, and Local Population References for the Prediction of Fetal Compromise: Which Is the Best Approach?

OBJECTIVE

The aim of this work was to compare the accuracy of the cerebroplacental ratio (CPR), Intergrowth 21st standards (IG21), customized growth (CG), and local population references (LPR) in the prediction of intrapartum fetal compromise (IFC).

METHODS

This was a prospective study of 714 fetuses that underwent an ultrasound examination at 34-41 weeks and were delivered within a 2-week interval. The CPR was converted into multiples of the median and the estimated fetal weight (EFW) transformed into CG, IG21, and LPR centiles. IFC was defined as a composite of abnormal cardiotocogram, intrapartum pH requiring cesarean section, 5-min Apgar score, and admission to pediatric care units. The accuracies of the CPR and the EFW centiles for the prediction of IFC were evaluated alone and in combination with other gestational characteristics using univariate and multivariate analysis.

RESULTS

Individually, the CPR was the parameter that best predicted the existence of IFC (AUC = 0.66). The multivariate analysis showed that the best prediction was again achieved with the CPR, alone or in combination with any of the EFW centiles (AUC = 0.74). No significant differences were seen between the different centile methods.

CONCLUSION

The best prediction of IFC is obtained with CPR. Evaluation of CPR should be encouraged in term and late-preterm fetuses.

Proximity of term labor deepens the fall of Doppler impedance in the fetal cerebral arteries

OBJECTIVE

To determine the existence of Doppler changes in the fetal vertebral, middle cerebral and umbilical arteries prior to term labor.

METHODS

Five hundred and twenty eight Doppler examinations of the vertebral (VA), middle cerebral (MCA) and umbilical (UA) arteries resistance indices (RI) were performed between 37 and 41 weeks gestation. For each artery, values were converted into multiples of the median (MoM) and were divided into four groups according to the interval to labor and compared using Kruskal-Wallis tests. Subsequently, values were plotted in scattergrams and linear regressions and 95% confidence intervals were calculated. Finally, using multivariate analysis and model averaging, the importance and interrelationship of Doppler measurements in the explanation of the interval to labor was evaluated.

RESULTS

Univariate and multivariate analysis confirmed that, independently of gestational age, fetuses examined close to labor presented more intense Doppler changes in the cerebral arteries with a significant reduction of the VA RI and MCA RI. This reduction was larger in the MCA. No significant changes were detected in the UA.

CONCLUSION

Before the onset of term labor, the fetal cerebral flow presents an additional reduction of impedance, which is more intense in the MCA system.