Early postnatal transitional circulation in fetal growth restricted neonates

Abstract

Background

Fetal growth restriction (FGR) may impact early postnatal transitional circulation.

Aim

Echocardiographic assessment of left ventricular cardiac output, superior vena cava (SVC) and ductus venosus (DV) blood flow in FGR neonates first three days after birth.

Study design

Prospective observational study.

Subjects

FGR and Non-FGR neonates.

Outcome measures

Left ventricular cardiac output, SVC and DV blood flow day one, two, and three.

Results

Adjusting for gestational age (GA), birth weight, sex, and twin/singleton, flow measurements were similar between Late-FGR (GA ≥ 32 weeks, n = 23) and Non-FGR (GA ≥ 32 weeks, n = 39). On day three, Late-FGR had significantly lower left ventricular stroke volume (Estimated Marginal Means (Standard Error) 0.99 (0.08) vs 1.22 (0.06) mL/kg, p = 0.027) and higher heart rate (134 (5) vs 119 (4) beats/min, p = 0.032). Left ventricular cardiac output and left ventricular stroke volume decreased significantly from day one to three in both groups; Late-FGR 170 (8) to 149 (8) mL/min/kg, p = 0.007, and 1.34 (0.07) to 1.17 (0.07) mL/kg, p = 0.015, and Non-FGR 161 (6) to 144 (6) mL/min/kg, p = 0.002, and 1.27 (0.06) to 1.16 (0.06) mL/kg, p = 0.021. SVC flow remained unchanged from day one to three in Late-FGR (92 (6) to 83 (6) mL/min/kg, p = 0.161) and decreased significantly in Non-FGR (83 (5) to 71 (5) mL/min/kg, p = 0.021). DV blood flow remained unchanged. No measurements differed between Early-FGR (GA 30⁺⁰–31⁺⁶ weeks) and Late-FGR.

Conclusions

Late-FGR had limited impact on left ventricular cardiac output, SVC and DV blood flow in early neonatal period. Most adaptive circulatory changes occurred early during transition.