Ito Y, Shono H, Shono M, Muro M, Uchiyama A, Sugimori H
Department of Obstetrics and Gynecology, Saga Medical School, Nabeshima, Japan.
Acta Obstet Gynecol Scand. 1998 Apr;77(4):385-90.
Our aim was to investigate the relationship between placental location and resistance index (RI) of uterine arteries in cases with intrauterine growth retardation (IUGR).
Placental location and flow velocity waveforms of uterine arteries in 86 normal and 20 IUGR cases from 33 to 38 weeks of gestation were examined using a combined real-time scanner and pulsed Doppler ultrasonography. The location of placenta was classified as lateral when most of it was located to either the right or the left side of the uterine midline. Otherwise it was called central. Cases where the placenta was located in the uterine fundus or in the lower segment were not included. RI values were calculated from the uterine arteries on the placental side, on the non-placental side and in case of central placentas as a mean of both uterine arteries. In normal cases, the calculations were done every second week from 33 to 38 weeks of gestation, and the difference in variance among three gestational ages in each artery was tested by a one-way ANOVA. In IUGR cases, a standard deviation score (SDS) was calculated individually in each artery as (RI - normal mean)/normal SD. Differences in SDS between three categories of uterine arteries were examined by non-parametric tests.
In normal cases, there was no significant difference in variance of RIs among three gestational ages in each category of arteries. In IUGR cases, SDSs on the placental side were higher than those on the non-placental side and those in central placenta, (p<0.01, Wilcoxon's and Mann Whitney's tests, respectively). SDSs in five of eight cases with central placentas were below 1.0. Two of 12 cases with lateral placentas had higher SDSs on the non-placental side than on the placental side and resulted in abruptio placentae.
Deviation of RIs in uterine arteries with IUGR could be affected by the pathologic conditions of the utero-placental blood flow on the placental side of lateral placenta rather than in central placenta and might be done by dramatic increase in resistance to flow of the myometrial vessels on the non-placental side.
我们的目的是研究宫内生长受限（IUGR）病例中胎盘位置与子宫动脉阻力指数（RI）之间的关系。
使用实时扫描仪和脉冲多普勒超声检查86例正常孕妇和20例IUGR孕妇在妊娠33至38周时的胎盘位置和子宫动脉血流速度波形。当胎盘大部分位于子宫中线右侧或左侧时，胎盘位置分类为侧位。否则称为中央位。胎盘位于子宫底部或下段的病例不包括在内。RI值从胎盘侧、非胎盘侧的子宫动脉计算得出，对于中央胎盘，则取两侧子宫动脉的平均值。在正常病例中，从妊娠33至38周每两周进行一次计算，并通过单因素方差分析检验各动脉三个孕周之间的方差差异。在IUGR病例中，分别计算每条动脉的标准差评分（SDS），公式为（RI - 正常均值）/正常标准差。通过非参数检验检查三类子宫动脉之间SDS的差异。
在正常病例中，各类动脉三个孕周之间RI的方差无显著差异。在IUGR病例中，胎盘侧的SDS高于非胎盘侧和中央胎盘的SDS（分别为p<0.01，Wilcoxon检验和Mann Whitney检验）。8例中央胎盘病例中有5例的SDS低于1.0。12例侧位胎盘病例中有2例非胎盘侧的SDS高于胎盘侧，导致胎盘早剥。
IUGR时子宫动脉RI的偏差可能受侧位胎盘胎盘侧子宫 - 胎盘血流病理状况的影响，而非中央胎盘，并且可能是由非胎盘侧子宫肌层血管血流阻力的急剧增加所致。
