Placental volume measurement by 3D-ultrasound in the first trimester and prediction of fetal growth

Introduction: Fetal growth restriction (IUGR) and macrosomia are associated with increased morbidity and mortality of the newborn. Increase in uterine blood flow resistance and reduction of placental size may be of clinical relevance in IUGR but not in macrosomia. It is on this background that we investigated whether placental volume measurement by 3D-ultrasound and uterine artery Doppler in the first trimester allow prediction of fetal weight at birth.

Methods: Inclusion criteria were: singleton pregnancy and gestational age between 11+0 and 13+6 weeks. Exclusion criteria were: smoking, pre-existing diabetes, fetal anomalies, serious maternal disease and maternal medication affecting fetal growth. In 183 patients uterine artery Doppler (mean PI, bilateral notching) and placental volumetry by 3D-ultrasound were routinely performed. The placental ratio (PR=placental volume: crown-rump-length) was calculated. Primary outcome variables were birth weight below the 10th and above the 90th percentile.

Results: Placental volume (p=0,002) and placental ratio (p=0,008) in the first trimester were significantly associated with percentile and fetal weight at birth. All other parameters demonstrated no significant effect. In multivariate analysis the placental ratio was the only parameter predicting fetal birth weight above the 90th but not below the 10th percentile at a significant level (p=0,01). Sensitivity and specificity of predicting IUGR and macosomia were tested and significantly associated with placental volume (p=0,01).

Conclusion: 3D-placental volumetry in the first trimester appears to be an early predictor of IUGR and macrosomia and of the percentile of fetal birth weight.

3D Ultrasound - fetal growth