Hedriana H L, Gilbert W M, Brace R A
Department of Reproductive Medicine, University of California at San Diego, La Jolla, USA.
J Soc Gynecol Investig. 1997 Jul-Aug;4(4):203-8.
To determine whether physiological increases in fetal plasma arginine vasopressin (AVP) concentration alter blood flow rates to the ovine chorion, amnion or placenta, and to determine whether these AVP-induced changes in flow are dependent on gestational age.
Colored microspheres (15.10 +/- 0.02 microns (standard deviation) were infused into the superior vena cava before and at 30, 75, and 125 minutes of an intravenous AVP infusion (3 ng/min/kg) in 9 chronically catheterized fetal sheep between 103 days to 141 days gestation (term = 147 days). Chorion, amnion, and placental cotyledons were removed, and microspheres were counted to determine blood flow rates.
Fetal arterial pressure (FAP) increased (analysis of variance, P < .0001) and heart rate (FHR) decreased (P < .0001) during the infusion, with responses greater in older (> 125 days) compared to younger (< 125 days) fetuses (P < .001). Chorionic blood flow rate increased by 19 +/- 7% at 30 min of the AVP infusion, and declined by 18 +/- 6% at 75 min, and 32 +/- 5% at 125 min (P < .0001). Similarly, fetal placental blood flow rate increased by 20 +/- 7% at 30 min of infusion, and declined, in parallel with chorionic blood flow rates, by 6 +/- 4% at 75 min, and 17 +/- 4% at 125 min (P < .0001). Amniotic blood flow rate did not change significantly during the infusion. The membranous and placental blood flow rate responses to AVP infusion did not depend upon gestational age.
Physiologic increases in plasma AVP concentration induce an early increase in chorionic blood flow followed by a gradual decrease which parallels similar changes in placental blood flow rate. Unlike FAP and FHR, these blood flow changes are not gestational age-dependent. AVP-induced blood flow changes could play an important role in determining abnormalities of amniotic fluid volume observed clinically in some stressed fetuses.
确定胎儿血浆中精氨酸加压素（AVP）浓度的生理性升高是否会改变绵羊绒毛膜、羊膜或胎盘的血流速度，并确定这些AVP诱导的血流变化是否依赖于胎龄。
在9只妊娠103天至141天（足月为147天）的慢性插管胎儿绵羊中，于静脉输注AVP（3 ng/min/kg）前及输注30、75和125分钟时，将彩色微球（15.10±0.02微米（标准差））注入上腔静脉。取出绒毛膜、羊膜和胎盘小叶，计数微球以确定血流速度。
输注期间胎儿动脉压（FAP）升高（方差分析，P<.0001），心率（FHR）降低（P<.0001），与较年轻（<125天）的胎儿相比，年龄较大（>125天）的胎儿反应更大（P<.001）。AVP输注30分钟时绒毛膜血流速度增加19±7%，75分钟时下降18±6%，125分钟时下降32±5%（P<.0001）。同样，胎儿胎盘血流速度在输注30分钟时增加20±7%，并与绒毛膜血流速度平行下降，75分钟时下降6±4%，125分钟时下降17±4%（P<.0001）。输注期间羊膜血流速度无显著变化。膜和胎盘血流速度对AVP输注的反应不依赖于胎龄。
血浆AVP浓度的生理性升高导致绒毛膜血流早期增加，随后逐渐减少，这与胎盘血流速度的类似变化平行。与FAP和FHR不同，这些血流变化不依赖于胎龄。AVP诱导的血流变化可能在确定临床上在一些应激胎儿中观察到的羊水过少异常方面发挥重要作用。
