Lang U, Baker R S, Khoury J, Clark K E
Department of Obstetrics and Gynecology, Justus-Liebig-University, 35385 Giessen, Germany.
Am J Physiol Regul Integr Comp Physiol. 2000 Jul;279(1):R53-9. doi: 10.1152/ajpregu.2000.279.1.R53.
Pregnancy is associated with a significant increase in uteroplacental blood flow (UBF), which is responsible for delivering adequate nutrients and oxygen for fetal and placental growth. The present study was designed to determine the effects of vascular insufficiency on fetal and placental growth. Thirty-nine late-term pregnant ewes were instrumented to investigate the effects of chronic UBF reduction. Animals were split into three groups based on uterine blood flow, and all animals were killed on gestational day 138. UBF, which began at 851 +/- 74 ml/min (n = 39), increased in controls (C) to 1,409 +/- 98 ml/min (day 138 of gestation) and in the moderately restricted (R(M)) group to 986 +/- 69 ml/min. In the severely restricted (R(S)) group, UBF was only 779 +/- 79 ml/min on gestational day 138. This reduction in UBF significantly affected fetal body weight with R(M) fetuses weighing 3,685 +/- 178 g and R(S) fetuses weighing 2,920 +/- 164 g compared with C fetal weights of 4,318 +/- 208 g. Fetal brain weight was not affected, whereas ponderal index was significantly reduced in R(M) (2.94 +/- 0.09) and R(S) fetuses (2.49 +/- 0.08) compared with the value of the C fetuses (3.31 +/- 0.08). Placental weight was also significantly reduced in the R(M) group, being 302 +/- 24 g, whereas the R(S) group placenta weighed 274 +/- 61 g compared with the C values of 414 +/- 57 g. Fetal heart, liver, lung, and thymus were all significantly smaller in the R(S) group. Thus the present study shows a clear relationship between the level of UBF and both fetal and placental size. Furthermore, the observation that fetal brain weight was not affected, whereas fetal body weight was significantly reduced suggests that this experimental preparation may provide a useful model in which to study asymmetric fetal growth restriction.
妊娠与子宫胎盘血流量（UBF）显著增加相关，子宫胎盘血流量负责为胎儿和胎盘生长输送充足的营养物质和氧气。本研究旨在确定血管功能不全对胎儿和胎盘生长的影响。对39只晚期妊娠母羊进行仪器监测，以研究慢性子宫胎盘血流量减少的影响。根据子宫血流量将动物分为三组，所有动物均在妊娠第138天处死。子宫胎盘血流量开始时为851±74毫升/分钟（n = 39），对照组（C）在妊娠第138天增加到1409±98毫升/分钟，中度受限（R(M)）组增加到986±69毫升/分钟。在严重受限（R(S)）组，妊娠第138天子宫胎盘血流量仅为779±79毫升/分钟。子宫胎盘血流量的这种减少显著影响胎儿体重，R(M)组胎儿体重为3685±178克，R(S)组胎儿体重为2920±164克，而C组胎儿体重为4318±208克。胎儿脑重未受影响，而与C组胎儿（3.31±0.08）相比，R(M)组（2.94±0.09）和R(S)组胎儿（2.49±0.08）的 ponderal指数显著降低。R(M)组胎盘重量也显著降低，为302±24克，而R(S)组胎盘重274±61克，C组为414±57克。R(S)组胎儿心脏、肝脏、肺和胸腺均明显较小。因此，本研究表明子宫胎盘血流量水平与胎儿和胎盘大小之间存在明确关系。此外，胎儿脑重未受影响而胎儿体重显著降低的观察结果表明，该实验模型可能为研究不对称性胎儿生长受限提供有用的模型。
