Investigation of intraplacental villous arteries by doppler flow imaging in growth-restricted fetuses

Abstract

Objective: The purposes of our study were to assess the ability of color and power Doppler sonography to depict the blood flow in the intraplacental villous arteries and to evaluate whether the blood flow of intraplacental villous arteries in a normal pregnancy is different from that in a pregnancy that is associated with intrauterine growth restriction. Study Design: Eighty-five women with uncomplicated pregnancy and 16 women with intrauterine growth-restricted fetuses between 27 and 38 weeks of gestation were examined by color and power Doppler imaging. The blood flow of intraplacental villous arteries was analyzed comparatively. The pulsatility index and peak systolic velocity were measured. Results: A unit of 1 intraplacental villous artery-1 and its branches were seen as 1 cotyledon by color and power Doppler imaging. The cotyledon was easily identified and counted. Each cotyledon contained only 1 intraplacental villous artery-1. This method can visualize the intraplacental villous artery-1 to intraplacental villous artery-4 in normal pregnancies. The terminal villous arteries beyond intraplacental villous artery-4 were not imaged. The number of detectable intraplacental villous artery-1 in 1 placenta in intrauterine growth restriction was significantly lower than that in normal pregnancy. The number of detectable branches in intrauterine growth restriction was also significantly lower than in normal pregnancy. No intraplacental villous artery-4 blood flow was found in women with intrauterine growth restriction. In examined arteries, pulsatility index decreased and peak systolic velocity increased significantly with advancing gestational age (P <.02). At any given gestational age, pulsatility index and peak systolic velocity in the peripheral arteries were significantly lower than those in the upstream arteries in normal pregnancy (P <.001). The pulsatility index value of each intraplacental villous artery was also lower than that of the umbilical artery in the women with intrauterine growth restriction (P <.05). There were no differences in pulsatility index in each artery between the groups, although there were a few high pulsatility index values in intrauterine growth restriction. Conclusion: Color Doppler and power flow sonography are valuable tools for the detection of the blood flow of intraplacental villous arteries. The decrease in the number of detectable intraplacental villous artery-1 and branches was associated with intrauterine growth retardation. (Am J Obstet Gynecol 2002;186:297-302.)