[A clinical evaluation of fetal wellbeing--based on fetal behavior with emphasis on conditions contributing to the dissociation of behavior].
The recent developments in Medical Electronics (M.E) have led to the possibility of noninvasive methods of evaluating conditions which previously were considered to be a "Black Box". Among the conditions now evaluable are fetal and placental morphology and functional aspects including fetal movements and behavioral studies. This has led to the discovery that the progressive development of the fetal Central Nervous System (CNS) is concurrent with the progression of fetal maturity and attainment of synchronicity of various fetal activities. This has led to the clinical application of ME for the evaluation of various fetal parameters in an attempt to assess fetal wellbeing. However in the presence of increase in frequency and strength of the various fetal activities with the advance of pregnancy, there is in fetuses of less than 28 weeks of development no synchronicity of the fetal activities, and in IUGR and fetuses under various forms of stress, the relationships between CNS development and fetal activity may become misaligned, or dissociated leading to the pitfall of misdiagnoses. Thus, in order to better understand the effects of chronic stress on the fetus we ran long term studies on pregnant ewes using physiologic and biochemical evaluations as our parameters for assessment. We observed a convergence of the various fetal behavior parameters with advancement of fetal age which we termed as the achievement of association of fetal behavior. However, when fetal hypoxemia is induced as a chronic condition, the phenomenon of convergence of the various behavioral parameters is inhibited, leading to a so called dissociation of those functions. Further, the greater the severity of the hypoxemia (stress), the greater the inhibitory effect on the convergence of the various activities, thus the greater the dissociation. A possible reason for this effect is the inhibition of respiratory activity. In order to clarify the hypothesis stated above, we induced hypoxemia in fetal lambs, as well injecting them with various materials. We found that AVP which increases in hypoxemia has no effect on pulse rate, but does inhibit respiratory activity, a clear representation of dissociation of fetal behavior. In conclusion, if fetal behavior is to be used as a method for evaluating wellbeing, it is necessary to also assess the convergence or association of the various behavioral parameters in order for it to be utilized as a clinical tool.
Sakata
H
H
Department of Obstetrics and Gynecology, Nihon University School of Medicine, Tokyo.
D000818:Animals; D001921:Brain / Q000196:embryology / Q000378:metabolism; D002395:Catecholamines / Q000378:metabolism; D005133:Eye Movements; D005260:Female; D005317:Fetal Growth Retardation / Q000503:physiopathology; D005311:Fetal Hypoxia / Q000503:physiopathology; D005324:Fetal Movement; D005325:Fetal Organ Maturity / Q000502:physiology; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011941:Receptors, Adrenergic / Q000378:metabolism; D017983:Receptors, Catecholamine; D011971:Receptors, Immunologic; D011982:Receptors, Prostaglandin / Q000378:metabolism; D012756:Sheep / Q000502:physiology
D002395:Catecholamines; D011941:Receptors, Adrenergic; D017983:Receptors, Catecholamine; D011971:Receptors, Immunologic; D011982:Receptors, Prostaglandin; C036293:prostaglandin D2 receptor