OP10.06: First trimester 3D-placental volumetry is a good predictor of both low and high birth weight

Abstract

Objective: The extremes of fetal weight are associated with serious perinatal complications and increased morbidity and mortality of the newborn. Early pathological changes in the placenta with reduction of its size and increase in uterine blood flow resistance may be of clinical relevance in intrauterine growth restriction but not in macrosomia. We therefore investigated whether placental volume parameters as assessed by 3D-ultrasound in the first trimester are related to 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 236 patients fetal biometry with regard to crown-rump-length (CRL), biparietal diameter (BIP) and abdominal circumference (AC) and placental volumetry by 3D-ultrasound were routinely performed. The placental volume (PV) and three different placental ratios (PR1=PV/CRL; PR2=PV/BIP; PR3=PV/AC) were calculated. Fetal birth weight below the 10th (SGA) and above the 90th percentile (macrosomia) served as primary outcome variables. Statistics were based on linear and logistic regression analysis. Results: 8.5% of our newborns were SGA and 11.9% macrosomic. The median of first trimester PV was 59.73 cm3. PV (p=0.001) and PR1-3 (p<0.0001) were significantly correlated with fetal weight at birth. In linear regression analysis highly significant effects on fetal birth weight were shown for all placental volume parameters. PV and placental ratios significantly predicted fetal birth weight below the 10th and above the 90th percentile in a logistic regression model. Conclusions: Different placental volume parameters in the first trimester show a strong correlation with fetal birth weight. 3Dplacental volumetry appears to be a useful technique in the early identification of pregnancies at risk for being SGA and macrosomic at birth.