REGIONAL VASCULAR CHANGES IN GROWTH RETARDED FETUS

非异常胎儿宫内发育迟缓的总发生率 胎儿宫内发育迟缓(IUGR)占所有新生儿的6%至7%。IUGR占总数的14% 死产和新生儿死亡总数的6%。身体解剖的结果是 这些胎儿/新生儿清楚地表明，肝、脾、 和肾脏，以及身体的长度都要小得多 胎儿与正常胎儿/新生儿相比。然而，大脑重量， 不要表现出这样的差异。因此，有一种不对称的器官生长 在这些非异常的IUGR胎儿中。器官生长的这种不对称性是 认为发生的原因是由于 心输出量。到目前为止，我们关于这个分布的大部分知识 正常胎儿或窒息胎儿的合并心输出量 是使用侵入性技术从实验动物身上获得的。 关于人类IUGR胎儿的数据缺乏。随着最近在 超声技术，彩色脉冲多普勒可用于定量 未受干扰的人胎儿全身和局部血流 环境。利用这项技术，我们已经获得了初步数据 这表明心脏的收缩能力和输出量与胎儿大小有关 与非对称性IUGR胎儿相比，差异不显著 给正常的胎儿。根据这些观察结果，我们假设 在受影响的人类胎儿身上一定会出现局部血流的差异 由非对称性IUGR。我们假设血液流动的变化 受IUGR影响的胎儿早期会出现肾脏和下肢，但 流向大脑中动脉的血流将保持不变，因此， 局部血流研究中的改变可以作为早期的 IUGR的标志物。彩色脉冲多普勒将有助于将微小的 血管结构并量化流向腿部、肾脏和 50例正常胎儿和50例非对称性宫内发育迟缓胎儿的脑组织。 这些多谱勒检查将在第18至20周左右开始 每4周重复一次，直到分娩。超音波 将分别测量胎头、腹部和股骨的尺寸。 多谱勒检查。脉冲多普勒也将被用来计算对 和左心输出量。我们还将在文件中记录是否存在此类更改 局部血流先于异常或与异常同时出现 身体生长，并将记录这种血流开始的时间 减少。我们预计区域血流量将发生变化 在超声确认生长减退之前。一个完整的 对人体局部血流分布的认识 胎儿有不对称性宫内发育迟缓风险又可能导致早产 对这种病理情况的诊断，并允许及早 干预。这种干预可能会反过来降低 与IUGR胎儿相关的发病率/死亡率。

The overall incidence of nonanomalous intrauterine growth retardation (IUGR) varies between 6 and 7% of all births. IUGR accounts for 14% of all stillbirths and 6% of all neonatal deaths. Results from autopsies done on these fetuses/newborns, clearly demonstrate that weights of liver, spleen, and kidneys, as well as body length are significantly smaller in these fetuses when compared to normal fetuses/newborns. Brain weights, however, do not show such differences. Thus, there is an asymmetrical organ growth in these nonanomalous IUGR fetuses. This asymmetry in organ growth is thought to occur because of an ALTERATION IN THE DISTRIBUTION of the cardiac output. To date, most of our knowledge regarding the distribution of the combined cardiac output in either the normal or asphyxiated fetus has been obtained from experimental animals using invasive techniques. Data in the human IUGR fetuses are lacking. With recent improvement in ultrasound technique, color pulsed Doppler can be applied to quantify systemic and regional blood flow in human fetuses in their undisturbed environment. Using this technique, we have obtained preliminary data which indicate that cardiac contractility and output indexed to fetal size is not significantly different in asymmetrical IUGR fetuses when compared to normal fetuses. We hypothesize as a result of these observations that differences in regional blood flows must occur in the human fetus affected by asymmetrical IUGR. We hypothesize that an alteration in blood flow to kidneys and lower limbs will occur early in fetuses affected by IUGR, but flow to the middle cerebral artery will be maintained and as such, ALTERATION in the study of regional blood flow could be used as an early marker for IUGR. Color pulsed Doppler will help to visualize small vascular structures and to quantify blood flow to the leg, kidney and brain of 50 normal human fetuses and in 50 fetuses with asymmetrical IUGR. These Doppler examinations will be started at around the 18th to 20th week of gestation and repeated every four weeks until delivery. Ultrasound measurements of the fetal head, abdomen and femur will be obtained at each Doppler examination. Pulsed Doppler will also be used to calculate right and left ventricular output. We will also document if such alteration in regional blood flow PRECEDES or is CONTEMPORANEOUS with the abnormal somatic growth and will document the time onset of this blood flow decrease. We anticipate that changes in regional blood flow will occur prior to ultrasound confirmation of decreased growth. A complete understanding in the distribution of regional blood flow in the human fetus at risk for asymmetrical IUGR may in turn lead to an earlier diagnosis of such pathological conditions and may permit early intervention. Such intervention may in turn decrease the morbidity/mortality associated with IUGR fetuses.