REGIONAL VASCULAR CHANGES IN GROWTH RETARDED FETUS

非异常胎儿宫内发育迟缓的总体发生率 （IUGR）在所有出生的6%至7%之间变化。IUGR占14%， 占所有新生儿死亡的6%。尸检结果显示 这些胎儿/新生儿清楚地表明，肝，脾， 和肾脏，以及身体的长度显着较小，在这些 与正常胎儿/新生儿相比。 然而，大脑重量， 并没有表现出这样的差异。 因此，存在不对称的器官生长 这些正常的IUGR胎儿。 这种器官生长的不对称性 被认为是由于分布的改变， 心输出量到目前为止，我们对分布的大部分了解 正常或窒息胎儿的心输出量 是通过侵入性技术从实验动物身上获得的。 缺乏人类IUGR胎儿的数据。随着最近的改善， 超声技术，彩色脉冲多普勒可用于定量 人胎儿体循环和局部血流 环境 利用这项技术，我们已经获得了初步的数据， 这表明心脏收缩力和输出量与胎儿大小有关， 在不对称IUGR胎儿中， 正常的胎儿根据这些观察结果，我们假设 受影响的人类胎儿一定存在局部血流的差异， 不对称IUGR。 我们假设血液流动的改变 肾脏和下肢将发生在胎儿宫内发育迟缓的早期，但 将维持到大脑中动脉的血流， 局部血流研究中的改变可以作为早期诊断的依据。 IUGR的标志物。彩色脉冲多普勒将有助于可视化小 血管结构，并量化流向腿部、肾脏和 对50例正常胎儿和50例不对称IUGR胎儿的脑组织进行了观察。 这些多普勒检查将在第18至20周左右开始 每四周重复一次，直到分娩。 超声 将在每个时间点测量胎头、腹部和股骨。 多普勒检查。 脉冲多普勒也将用于计算右 和左心室输出量。我们还将记录此类变更， 局部血流先于异常或与异常同时发生 并将记录这种血流的时间开始 减少。我们预计局部血流会发生变化 在超声波确认生长减缓之前 一个完整 对人体局部血流分布的认识 有不对称IUGR风险的胎儿可能反过来导致早期 诊断这种病理状况，并可能允许早期 干预这种干预反过来可能会减少 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.