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Modalities of fetal evaluation to detect fetal compromise prior to the development of significant neurological damage
Author(s) -
Maeda Kazuo
Publication year - 2014
Publication title -
journal of obstetrics and gynaecology research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.597
H-Index - 50
eISSN - 1447-0756
pISSN - 1341-8076
DOI - 10.1111/jog.12481
Subject(s) - medicine , modalities , fetus , compromise , fetal monitoring , intensive care medicine , pregnancy , genetics , biology , social science , sociology
Abstract Aims The aim of this study was to clarify the developmental mechanism underlying fetal heart rate ( FHR ) long‐term variability ( LTV ) and acceleration with respect to fetal brain damage. Material and Methods The fetal state was deduced from the developmental mechanism of FHR variability analyzed by actocardiogram, animal experiments, and simulations. Results LTV develops due to minor fetal movements in the fetal midbrain, moderate LTV by fetal periodic movements and triangular accelerations by large fetal movement bursts. Stimulation of the fetal midbrain by sound and light produces fetal movements that lead to FHR acceleration. Severe hypoxia can result in the loss of LTV and neuronal necrosis that may damage the fetal brain. Therefore, a cesarean section is recommended prior to the loss of LTV , rather than after its loss. The vagal center of the fetal medulla oblongata is excited by hypoxia and produces FHR bradycardia. The heart rate of hypoxic rabbits was found to be closely correlated with the PaO 2 , thus the impact of hypoxia could be estimated by the hypoxia index, which is calculated from the reciprocal of nadir FHR and bradycardia duration. Conclusions Analyzing the development of FHR signs could help to diagnose fetal state. An early cesarean section is recommended before the loss of LTV as indicated by the hypoxia index, which will contribute to prevent fetal brain damage and neurological sequels.