Background

The functional maternal-fetal hemodynamic unit includes fetal umbilical vein flow and maternal peripheral vascular resistance.

Objective

This study investigated the relationships between maternal and fetal hemodynamics in a population with suspected fetal growth restriction.

Study Design

This was a prospective study of normotensive pregnancies referred to our outpatient clinic for a suspected fetal growth restriction. Maternal hemodynamics measurement was performed, using a noninvasive device (USCOM-1A) and a fetal ultrasound evaluation to assess fetal biometry and velocimetry Doppler parameters. Comparisons among groups were performed with 1-way analysis of variance with Student-Newman-Keuls correction for multiple comparisons and with Kruskal-Wallis test where appropriate. The Spearman rank coefficient was used to assess the correlation between maternal and fetal hemodynamics. Pregnancies were observed until delivery.

Results

A total of 182 normotensive pregnancies were included. After the evaluation, 54 fetuses were classified as growth restricted, 42 as small for gestational age, and 86 as adequate for gestational age. The fetus with fetal growth restriction had significantly lower umbilical vein diameter (P<.0001), umbilical vein velocity (P=.02), umbilical vein flow (P<.0001), and umbilical vein flow corrected for fetal weight (P<.01) than adequate-for-gestational-age and small-for-gestational-age fetuses. The maternal hemodynamic profile in fetal growth restriction was characterized by elevated systemic vascular resistance and reduced cardiac output. The umbilical vein diameter was positively correlated to maternal cardiac output (r_s=0.261), whereas there was a negative correlation between maternal systemic vascular resistance (r_s=−0.338) and maternal potential energy–to–kinetic energy ratio (r_s=−0267). The fetal umbilical vein time averaged max velocity was positively correlated to maternal cardiac output (r_s=0.189) and maternal inotropy index (r_s=0.162), whereas there was a negative correlation with maternal systemic vascular resistance (r_s=−0.264) and maternal potential energy–to–kinetic energy ratio (r_s=−0.171). The fetal umbilical vein flow and the flow corrected for estimated fetal weight were positively correlated with maternal cardiac output (r_s=0.339 and r_s=0.297) and maternal inotropy index (r_s=0.217 and r=0.336), whereas there was a negative correlation between maternal systemic vascular resistance (r_s=−0.461 and r_s=−0.409) and maternal potential energy–to–kinetic energy ratio (r_s=−0.336 and r_s=−0.408).

Conclusion

Maternal and fetal hemodynamic parameters were different in the 3 groups of fetuses: fetal growth restriction, small for gestational age, and adequate for gestational age. Maternal hemodynamic parameters were closely and continuously correlated with fetal hemodynamic features. In particular, a maternal hemodynamic profile with high systemic vascular resistance, low cardiac output, reduced inotropism, and hypodynamic circulation was correlated with a reduced umbilical vein flow and increased umbilical artery pulsatility index. The mother, placenta, and fetus should be considered as a single cardiac-fetal-placental unit. The correlations of systemic vascular resistance, cardiac output, and inotropy index with umbilical artery impedance indicate the key role of these 3 parameters in placental vascular tree development. The umbilical vein flow rate and, therefore, the placental perfusion seems to be influenced not only by these three parameters but also by the maternal cardiovascular kinetic energy.

中文翻译：

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心脏-胎儿-胎盘单元：胎儿脐静脉流速与胎儿生长受限中的母体心脏状况有关

背景

功能性母胎血流动力学单位包括胎儿脐静脉流量和母体外周血管阻力。

客观的

本研究调查了疑似胎儿生长受限人群中母体和胎儿血流动力学之间的关系。

学习规划

这是一项针对因疑似胎儿生长受限转诊至我们门诊的血压正常妊娠的前瞻性研究。使用无创设备 (USCOM-1A) 和胎儿超声评估来评估胎儿生物测量和测速多普勒参数，进行母体血流动力学测量。组间比较采用单向方差分析，Student-Newman-Keuls 校正用于多重比较，并在适当时采用 Kruskal-Wallis 检验。Spearman 等级系数用于评估母体和胎儿血流动力学之间的相关性。观察妊娠直至分娩。

结果

总共包括 182 例血压正常的妊娠。评估后，54 名胎儿被归类为生长受限，42 名胎儿小于胎龄，86 名胎儿适合胎龄。胎儿生长受限的胎儿脐静脉直径 ( P <.0001)、脐静脉速度 ( P =.02)、脐静脉流量 ( P <.0001) 和根据胎儿体重校正的脐静脉流量 ( P <.0001 ) 显着降低.01) 低于适足胎龄儿和小于胎龄儿。胎儿生长受限的母体血流动力学特征表现为全身血管阻力升高和心输出量降低。脐静脉直径与母体心输出量呈正相关（r _{s=0.261)，而母体全身血管阻力 ( rs} =−0.338) 与母体势能动能比 (rs ₌ −0267)呈负相关。_{胎儿脐静脉时间平均最大流速与母体心输出量（r s} =0.189）和母体肌力指数（r _s =0.162）呈正相关，而与母体全身血管阻力呈负相关（r _s =-0.264）和母体势能与动能之比 (r _s =−0.171)。胎儿脐静脉流量和根据估计的胎儿体重校正的流量与母体心输出量呈正相关（r _s = 0.339 和 r _s=0.297) 和母体肌力指数（rs _{= 0.217 和 r=0.336），而母体全身血管阻力（ rs} =−0.461 和 rs ₌ −0.409）与母体势能-动能呈负相关能量比（r _s =-0.336 和 r _s =-0.408）。

结论

3组胎儿的母胎血流动力学参数不同：胎儿生长受限、小于胎龄儿和足胎龄儿。母体血流动力学参数与胎儿血流动力学特征密切且持续相关。特别是，具有高全身血管阻力、低心输出量、正性肌力减少和低动力循环的母体血流动力学特征与脐静脉流量减少和脐动脉搏动指数增加相关。母亲、胎盘和胎儿应被视为一个单一的心脏-胎儿-胎盘单位。全身血管阻力、心输出量和肌力指数与脐动脉阻抗的相关性表明这 3 个参数在胎盘血管树发育中的关键作用。