Kidney impairment in fetal growth restriction: three-dimensional evaluation of volume and vascularization.

OBJECTIVES: Renal development is impaired in fetal growth restriction (FGR). Renal size can be considered a surrogate of renal function in childhood, and could be impaired in that condition. Our aim was to evaluate the ratio of total renal volume, measured by three-dimensional ultrasound, to estimated fetal weight (TRV/EFW) among fetuses with and without growth restriction. Furthermore, we correlated TRV/EFW with fetal Doppler velocimetry and renal vascularization indexes and evaluated the association of renal volume and vascular parameters with adverse neonatal events in growth-restricted fetuses. METHODS: In a retrospective cohort, TRV and renal vascularization of growth-restricted and normal fetuses were evaluated by three-dimensional ultrasonography and VOCAL technique. Independent samples t-tests and Mann-Whitney test were used for comparisons between groups. Logistic regression model was applied to evaluate the association between renal characteristics and adverse neonatal events. RESULTS: Seventy-one growth-restricted fetuses were compared to 194 controls. The TRV/EFW was lower in the growth-restricted group (P < .001). In our sample, this ratio did not correlate with Doppler velocimetry parameters, renal vascular indexes or any adverse neonatal events. CONCLUSION: The TRV/EFW ratio is decreased in FGR. Further studies are needed to investigate the association of this ratio with long-term renal outcomes.

Renal vascularization indexes and fetal hemodynamics in fetuses with growth restriction.

OBJECTIVE: To identify the correlation between the renal vascularization index (VI), the flow index (FI) and the vascularization and flow index (VFI) and placental and fetal hemodynamics in fetuses with growth restriction. METHOD: Bidimensional ultrasound and three-dimensional power Doppler with the VOCAL technique were used to determine the renal vascular indexes and fetal and placental hemodynamics in fetuses below the 10th percentile for fetal weight. Partial correlation analysis (controlled for renal depth and gestational age) was performed. The fetuses were divided into four groups according to their hemodynamic picture, and renal indexes were compared between the groups. RESULTS: Eighty-one fetuses were evaluated. VI, FI and VFI showed negative correlation with the ductus venosus pulsatility index. VI and VFI showed positive correlations with the amniotic fluid index. The group of fetuses with the worst hemodynamic picture (abnormal umbilical artery, middle cerebral artery and ductus venosus pulsatility indexes) showed significantly lower VI and VFI than the group with no changes in these pulsatility indexes. CONCLUSIONS: Renal vascularization indexes were inversely correlated with ductus venosus pulsatility indexes and were diminished in fetuses showing hemodynamic compromise. These changes might be related to postnatal renal impairment. © 2017 John Wiley & Sons, Ltd.

Reduced placental volume and flow in severe growth restricted fetuses.

OBJECTIVES: To evaluate placental volume and vascular indices in pregnancies with severe fetal growth restriction and determine their correlations to normal reference ranges and Doppler velocimetry results of uterine and umbilical arteries. METHODS: Twenty-seven fetuses with estimated weights below the 3rd percentile for gestational age were evaluated. Placental volume and vascular indices, including vascularization, flow, and vascularization flow indices, were measured by three-dimensional ultrasound using a rotational technique and compared to a previously described nomogram. The observed-to-expected placental volume ratio for gestational age and observed-to-expected placental volume ratio for fetal weight were calculated. Placental parameters correlated with the Doppler velocimetry results of uterine and umbilical arteries. RESULTS: The mean uterine artery pulsatility index was negatively correlated with the observed-to-expected placental volume ratio for gestational age, vascularization index and vascularization flow index. The observed-to-expected placental volume ratio for gestational age and observed-to-expected placental volume ratio for fetal weight and vascularization index were significantly lower in the group with a bilateral protodiastolic notch. No placental parameter correlated with the umbilical artery pulsatility index. CONCLUSIONS: Pregnancies complicated by severe fetal growth restriction are associated with reduced placental volume and vascularization. These findings are related to changes in uterine artery Doppler velocimetry. Future studies on managing severe fetal growth restriction should focus on combined results of placental three-dimensional ultrasound and Doppler studies of uterine arteries.

Reduced placental volume and flow in severe growth restricted fetuses

OBJECTIVES: To evaluate placental volume and vascular indices in pregnancies with severe fetal growth restriction and determine their correlations to normal reference ranges and Doppler velocimetry results of uterine and umbilical arteries. METHODS: Twenty-seven fetuses with estimated weights below the 3rd percentile for gestational age were evaluated. Placental volume and vascular indices, including vascularization, flow, and vascularization flow indices, were measured by three-dimensional ultrasound using a rotational technique and compared to a previously described nomogram. The observed-to-expected placental volume ratio for gestational age and observed-to-expected placental volume ratio for fetal weight were calculated. Placental parameters correlated with the Doppler velocimetry results of uterine and umbilical arteries. RESULTS: The mean uterine artery pulsatility index was negatively correlated with the observed-to-expected placental volume ratio for gestational age, vascularization index and vascularization flow index. The observed-to-expected placental volume ratio for gestational age and observed-to-expected placental volume ratio for fetal weight and vascularization index were significantly lower in the group with a bilateral protodiastolic notch. No placental parameter correlated with the umbilical artery pulsatility index. CONCLUSIONS: Pregnancies complicated by severe fetal growth restriction are associated with reduced placental volume and vascularization. These findings are related to changes in uterine artery Doppler velocimetry. Future studies on managing severe fetal growth restriction should focus on combined results of placental three-dimensional ultrasound and Doppler studies of uterine arteries.