The hemodynamic repercussions of the autonomic modulations in growth-restricted fetuses

Abstract

Objectives

Idiopathic fetal growth restriction is considered to be associated with hemodynamic abnormalities.

The study was aimed to the investigation of the relationship between fetal and maternal autonomic balance, arterial and venous hemodynamic Doppler indices and CTG variables in case of normal fetal development and fetal growth restriction.

Method 106 patients at 32–40 weeks of gestation were enrolled in the study. 30 of them had healthy pregnancy and were involved in Group I. In Group II, 44 pregnant women with fetal growth restriction and normal umbilical hemodynamic Doppler indices were observed. 32 patients with fetal growth restriction and an absent or reversed end-diastolic umbilical flow were monitored in Group III. The curves of maximum blood flow velocity were isolated and their spectral components were determined from the umbilical Doppler spectrograms. The maternal and fetal heart rate variability, conventional CTG patterns were obtained from RR-interval time series registered from maternal abdominal wall electrocardiographically. Results The increased adrenergic regulation has modulated parasympathetic impact on fetal cardiovascular system. The decreased reactivity was mirrored in low LTV, lack of accelerations and an increased score of decelerations. The CTG findings were also featured by the revealed correlations demonstrated an obvious relationship between fetal and maternal hemodynamics in healthy pregnancy. It was possible to speculate that a controlling signal of 0.5 Hz has played a significant role in the umbilical venous blood flow. The decreased fetal autonomic tone and the fetal and maternal hemodynamic decoupling were found in growth-retarded fetuses. Conclusion Fetal heart rate pattern was influenced by maternal and fetal autonomic tone. Maternal cardiovascular oscillations were reflected in the umbilical circulation in healthy pregnancy Fetal distress was featured by sympathetic overactivity and the reduction of vagal tone. Such autonomic modulations was manifested by the decelerative pattern of CTG and deteriorated umbilical hemodynamics.