A longitudinal study of three-dimensional ultrasonographic assessment of the placenta in uncomplicated pregnancies

Abstract

Placental vascularization is important for normal pregnancy. The circulatory function of the placenta appears at an early stage of embryo-placental development and is strongly related to fetal growth, placental volume, and uterine blood flow. Therefore, adequate placental angiogenesis is critical for the establishment of normal placental vascularization with subsequent normal development of the fetus [1,2]. Recent advances in technology allow the combination of 3-dimensional (3-D) ultrasound with power Doppler, making it possible to quantify Doppler signals in a volume obtained by 3D scanning and allowing investigation of the placental circulation. Each calculation of the vascularization index (VI), flow index (FI), and vascularization-flow index (VFI) is defined through technological quantification, and these indices are thought to reflect the number of vessels within the volume of interest, the intensity of flow at the time of the 3-D sweep, and both blood flow and vascularization [3]. ORIGINAL ARTICLEKorean J Obstet Gynecol 2012;55 (7) ObjectiveThe purpose of our study was to investigate the relationship between birth weight and 3-dimensional (3D) power Doppler histogram of the placenta in the first-and second-trimester of uncomplicated pregnancies. MethodsIn this longitudinal study, 3D power Doppler ultrasound was performed in 54 non-smoking women with uncomplicated pregnancies at 10 to 13 weeks of gestation and subsequently at 19 to 22 weeks. A correlation and regression analysis was performed for placental volume (PV) and vascular indices versus clinical and sonographic variables. ResultsAll vascular indices of the second-trimester were significantly greater than values of the first-trimester. Placental vascular indices showed an incremental tendency with birth weight, which was only statistically significant when the flow index (FI) of the firsttrimester was considered (P=0.02). The PV of both the first-and second-trimester has a negative correlation with FI of the secondtrimester. ConclusionOur findings suggest that FI of the placenta in the first-trimester significantly affects growth of the fetus and placenta, likely reflecting the degree of placental vascularization during the first-trimester.