The following is a summary of “Cardiac-fetal-placental unit: fetal umbilical vein flow rate is linked to the maternal cardiac profile in fetal growth restriction,” published in the FEBRUARY 2023 issue of Obstetrics and Gynecology by Valensise, et al.

For a study, researchers sought to investigate the relationship between maternal and fetal hemodynamics in pregnant women with suspected fetal growth restriction. 

The study included 182 normotensive pregnant women evaluated for fetal biometry and velocimetry Doppler parameters using fetal ultrasound and maternal hemodynamics using a noninvasive device (USCOM-1A). When necessary, the Kruskal-Wallis test and Student-Newman-Keuls correction for multiple comparisons was used to compare the groups in a 1-way analysis of variance. In addition, the correlation between the hemodynamics of the mother and the fetus was evaluated using the Spearman rank coefficient. Pregnancy was monitored up until birth.

After evaluation, the fetuses were classified into three groups: growth restricted (54), small for gestational age (42), and adequate for gestational age (86). The study found that the fetal umbilical vein diameter (P<.0001), velocity (P=.02), and flow rate (P<.0001) were significantly lower in the growth-restricted group compared to the other two groups. The circulatory system of pregnant women experiencing fetal growth restriction showed increased systemic vascular resistance and decreased cardiac output. 

There was a positive correlation between the diameter of the umbilical vein and maternal cardiac output (r=0.261) and negative correlations between maternal systemic vascular resistance (rs=−0.338) and maternal potential energy-to-kinetic energy ratio (rs=−0.267). The fetal umbilical vein’s time-averaged maximum velocity was positively correlated with maternal cardiac output (rs=0.189) and maternal inotropy index (rs=0.162) while negatively correlated with maternal systemic vascular resistance (rs=−0.264) and maternal potential energy-to-kinetic energy ratio (rs=−0.171). Additionally, the fetal umbilical vein flow and flow adjusted for estimated fetal weight showed positive correlations with maternal cardiac output (rs=0.339 and rs=0.297) and maternal inotropy index (rs=0.217 and rs=0.336) and negative correlations with maternal systemic vascular resistance (rs=−0.461 and rs=−0.409) and maternal potential energy-to-kinetic energy ratio (rs=−0.336 and rs=−0.408).

The findings suggested that maternal hemodynamics was crucial in fetal growth and development. The mother, placenta, and fetus should be considered a single cardiac-fetal-placental unit. The study highlighted the importance of monitoring maternal hemodynamics to identify fetal growth restriction and the need for timely intervention to prevent adverse perinatal outcomes.