OP08.11: Placental volume measurement by 3D ultrasound in the first trimester and prediction of fetal growth restriction

Abstract

Fetal growth restriction (IUGR) is associated with increased morbidity and mortality of the newborn. Reduced placental function because of impaired trophoblast invasion in the first trimester is an important pathogenetic factor. In this context increase in uterine blood flow resistance and reduction of placental size may be of clinical relevance. 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. 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 our prospective cohort study of 80 patients uterine artery Doppler (mean pulsatilitiy index, bilateral notching) and placental volumetry by 3D ultrasound were routinely performed and the placental ratio (PR = placental volume : crown − rump length) was calculated. Primary outcome variables were birth weight below or above the 10th percentile in our population. Statistics were based on logistic regression analysis. Sensitivity and specificity of predicting fetal birth weight below the 10th percentile were tested. Maternal body mass index (P = 0.043) and placental ratio (P < 0.001) were significantly associated with fetal birth weight in univariate regression analysis. All other parameters demonstrated no significant effect. In multivariate analysis the placental ratio was the only parameter predicting fetal birth weight category at a significant level (P = 0.002), with a sensitivity of 60% and a specificity of 72%. 3D-placental volumetry in the first trimester appears to be an early predictor of IUGR and the percentile of fetal birth weigth.