Effective early predictors of adverse obstetric outcomes are lacking. We sought to determine whether volumetric assessment of the early placenta can predict adverse obstetric outcome.
In this prospective cohort study, we obtained 3D placental volumes at 11-14 weeks. The VOCAL application of 4DVIEW (GE) was used to calculate placental volume (PV). PV was normalized to CRL to yield the placental quotient (PQ=PV/CRL). In addition, we measured the distance from the cord insertion to the nearest placental margin every 45 degrees around the placental circumference (8 measurements). The mean of these values, mean cord distance (MCD), is intended to serve as a novel descriptor of the chorionic plate and the centricity of the cord insertion. PQ and MCD were analyzed as predictors of a composite adverse outcome (COMP=SGA [BW<10th percentile], PEC, SPTB<37 wk, NICU admission). T-tests were used to compare mean values. ROC curves were constructed to determine optimal cut-points for each independent variable.
135 subjects were included. 40 (29.6%) had a composite adverse outcome (SGA-23, PEC-7, PTB-4, NICU-14). PV did not vary with maternal age, parity, BMI or ethnicity. Mean PQ (1.08, 0.97-1.19 vs 1.20, 1.15-1.25; p=0.04) and MCD (4.03, 3.85-4.21 vs 4.29, 4.17-4.40; p=0.02) were significantly lower in pts with COMP. PQ<1.00 conferred an increased risk for COMP (OR- 3.5, 1.6-7.34, P<0.002), with a specificity of 77.9% (68.2-85.8) and sensitivity of 50% (33.8-66.2). Similarly, MCD<4.00 was associated with COMP (OR-2.3, 1.1-4.9, p=0.03), with a specificity of 69.5%, (59-79) and sensitivity of 50% (34-66). Secondary analysis using SGA as the outcome also yielded significant associations (PQ: OR-3.9, 1.5-9.87; MCD: OR-4.3, 1.7-11.1).
Small placental volume and eccentric cord insertion are significantly associated with adverse perinatal outcome and may serve as biologically plausible predictors of placental dysfunction. Further research is warranted to investigate the optimal application of these novel 3D ultrasound techniques.
© 2009 Mosby, Inc. Published by Elsevier Inc. All rights reserved.