530 Uterine artery volumes, small for gestational age, preeclampsia, and adverse neonatal outcomes

Abstract

To determine if uterine artery flow volume (UtaV) estimated throughout gestation is different in pregnancies complicated by SGA, pre-eclampsia (PE), or adverse neonatal outcomes; to evaluate the potential of using UtaV as a screening tool when combined with maternal characteristics. This prospective longitudinal study over a 5-year period measured uterine artery vessel diameter and time-averaged maximum velocity (TAMXV) using color Doppler between 11+0 to 14+0, 18+0 to 22+6, and 28+0 to 34+6 weeks of gestation. UtaV was calculated from the vessel diameter and TAMXV. SGA was defined as birthweight < 10th percentile. PE was defined using ACOG criteria. A composite adverse neonatal outcome (ANO) was defined including presence of any of the following: 5 min Apgar score <5, arterial pH <7.10, respiratory distress syndrome, grade III or IVH (III or IV), seizures or neonatal death. Student t-tests were used to compared UtaV between normal and complicated pregnancies. ROC curves were constructed and AUCs compared. 397 pregnancies were included. Among pregnancies evaluated, SGA was seen in 26 (6.5%), PE in 22 (5.7%) and ANO in 22 (3.5%). The UtaV increased with gestational age (Figure). UtaV was significantly lower in SGA neonates in all trimesters but not in ANO (Table). UtaV was only significantly different in PE in the third-trimester. This difference persisted when UtaV was corrected for estimated fetal weight at the time of estimation (p=0.02). Prediction models for SGA including maternal characteristics: race, body mass index, smoking, hypertension, pre-gestational diabetes and UtaV had areas under the ROC curves of 0.68, 0.69 and 0.71 in first, second, and third trimesters, respectively. For PE, the AUC was 0.83, 0.82, 0.81, respectively. Uterine artery blood flow in all trimesters is reduced in pregnancies resulting in SGA. In pregnancies resulting in PE, UtaV was reduced in the third trimester. When combined with maternal characteristics, UtaV represents a promising screening marker for SGA and PE.View Large Image Figure ViewerDownload Hi-res image Download (PPT)