Morales-Roselló José, Khalil Asma, Ferri-Folch Blanca, Perales-Marín Alfredo
Servicio de Obstetricia, Hospital Universitario y Politécnico La Fe, Valencia, Spain.
Fetal Diagn Ther. 2015;38(2):103-12. doi: 10.1159/000371706. Epub 2015 Mar 14.
A low cerebro-placental ratio (CPR) at term suggests the existence of failure to reach growth potential (FRGP) with a higher risk of poor neonatal acid-base status. This study aimed to evaluate whether similar findings were also seen in the vertebral artery (vertebro-placental ratio, VPR), supplying 30% of the cerebral flow.
We studied term fetuses classified into groups according to birth weight (BW), CPR and VPR. BW was expressed in centiles and ratios in multiples of the median (MoM). Subsequently, associations with neonatal pH values were evaluated by means of regression curves and Mann-Whitney tests.
VPR MoM correlated with BW centiles (p < 0.0001, R2 = 0.042) and its distribution resembled that of CPR MoM (p < 0.001). When both arteries were compared, adequate-for-gestational-age (AGA) fetuses with either low CPR or low VPR had lower neonatal venous pH values (p < 0.05, p < 0.01, respectively). However, in case of small-for-gestational-age (SGA) fetuses, only those with low VPR had significantly lower neonatal arterial and venous pH values (p < 0.05).
Blood flow in the vertebral artery mimics that in the middle cerebral artery supporting the FRGP model. Both CPR and VPR identify AGA fetuses with lower neonatal pH values, but only VPR identifies SGA with lower pH values. Hypoxemia might be reflected as a generalized cerebral vasodilation demonstrated as low CPR and VPR.
足月时低脑胎盘比值（CPR）提示存在生长潜能未达标的情况（FRGP），且新生儿酸碱状态不良风险更高。本研究旨在评估在供应30%脑血流量的椎动脉（椎胎盘比值，VPR）中是否也能观察到类似结果。
我们研究了根据出生体重（BW）、CPR和VPR分类的足月胎儿。BW以百分位数表示，比值以中位数倍数（MoM）表示。随后，通过回归曲线和曼-惠特尼检验评估与新生儿pH值的相关性。
VPR MoM与BW百分位数相关（p < 0.0001，R2 = 0.042），其分布与CPR MoM相似（p < 0.001）。当比较两条动脉时，CPR或VPR较低的适于胎龄（AGA）胎儿的新生儿静脉pH值较低（分别为p < 0.05，p < 0.01）。然而，对于小于胎龄（SGA）胎儿，只有VPR较低的胎儿其新生儿动脉和静脉pH值显著较低（p < 0.05）。
椎动脉血流与大脑中动脉血流相似，支持FRGP模型。CPR和VPR均可识别出新生儿pH值较低的AGA胎儿，但只有VPR能识别出pH值较低的SGA胎儿。低氧血症可能表现为全身性脑血管舒张，表现为低CPR和VPR。
