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Updated: Aug 24, 2026
Fetal Echocardiography and Pulsed-wave Doppler Ultrasound in a Rabbit Model of Intrauterine Growth Restriction
Published on: June 29, 2013
Fetal heart rate and umbilical artery flow velocity variability in intrauterine growth restriction: a matched
A S M Vinkesteijn1, P C Struijk, N T C Ursem
1Department of Obstetrics and Gynaecology, Erasmus Medical Centre, Rotterdam, The Netherlands.
Insights
Fetal growth restriction is linked to reduced heart rate variability, suggesting altered autonomic nervous system balance. Umbilical artery blood flow velocity variability is not significantly impacted in these cases.
Area of Science:
- Fetal Physiology
- Neonatal Medicine
- Cardiovascular Research
Background:
- Fetal growth restriction (FGR) is a significant concern in high-risk pregnancies.
- The autonomic nervous system (ANS) plays a crucial role in fetal development and well-being.
- Assessing fetal autonomic function is vital for understanding FGR pathophysiology.
Purpose of the Study:
- To investigate heart rate variability (HRV) and umbilical artery blood flow velocity variability (VFV) in fetuses with FGR.
- To explore the influence of the autonomic nervous system on these parameters in FGR.
- To compare HRV and VFV between growth-restricted and normal fetuses.
Main Methods:
- Doppler velocimetry of umbilical arteries in 15 FGR fetuses and 15 controls (23-35 weeks gestation).
- Analysis of absolute velocities, coefficient of variation, and power spectral analysis for HRV and VFV.
- Calculation of the low-to-high (LH) ratio of HRV and VFV to assess sympathovagal balance.
Main Results:
- Significantly reduced umbilical artery velocities were observed in FGR fetuses.
- HRV was significantly decreased in FGR fetuses.
- No significant difference was found in VFV between FGR and control groups.
- The LH ratio for HRV was significantly decreased in FGR, indicating altered sympathovagal balance.
Conclusions:
- Decreased HRV in FGR appears influenced by an altered sympathetic-parasympathetic balance.
- VFV in FGR does not seem to be predominantly affected by the autonomic nervous system.
- These findings highlight distinct autonomic influences on fetal cardiovascular parameters in FGR.
Objectives:
To study heart rate and umbilical artery blood flow velocity variability in growth-restricted fetuses and investigate the influence of the autonomic nervous system on these parameters.
Methods:
Doppler velocity waveforms were collected from long-lasting umbilical artery recordings in 15 fetuses with growth restriction and 15 normal age-matched controls at 23-35 weeks of gestation. Absolute heart rate and umbilical artery blood flow velocity as well as the coefficient of variation were determined. Using power spectral analysis the low- and high-frequency bands of heart rate variability and blood flow velocity variability were calculated. The low-to-high (LH) ratio of heart rate variability and blood flow velocity variability were examined as a measure of sympathovagal balance.
Results:
In growth-restricted fetuses umbilical artery velocities were significantly reduced. Heart rate variability was significantly reduced in the presence of growth restriction, but no significant difference was demonstrated for blood flow velocity variability. The LH ratio for heart rate variability was significantly decreased in growth restriction, but no difference in LH ratio was demonstrated for blood flow velocity variability.
Conclusion:
Flow velocity variability in growth restriction seems not to be predominantly influenced by the autonomic nervous system, whereas the decreased heart rate variability seems to be influenced by altered sympathetic-parasympathetic balance.
