足月胎儿对声音刺激反应的探讨

THE RESPONSES OF TERM FETUSES TO DIFFERENT ACOUSTIC STIMULATIONS

通过观察声音刺激引起胎儿产生的胎动和胎心率反应 ,初步探讨声音刺激能否引起胎儿的感觉和相应的反射机制。选择正常足月孕妇 94例 ,分别接受 95、10 0、10 5、110、115dB的声音刺激 ,观察胎儿的胎动和胎心率反应。95dB声音能引起胎心率轻度下降且不引起胎动 ,而声强在 10 0dB以上的声音刺激能引起胎心率加速并伴有胎动 ,提示 95dB声音可以引起胎儿的定向反射 ,和胎儿的选择性的注意有关 ;而 10 0～ 115dB的声音能引起胎儿的防卫反应。

Objective To explore the characteristic fetal movement and FHR response elicited by acoustic stimulation and whether acoustic stimulation can induce fetal sensation. Methods Ninety-four pregnant women were recruited from Woman's hospital, Medical School, Zhejiang University. All fetuses were at term.Stimuli-evoked fetal movements and FHR responses to acoustic stimulation with five different intensities at 95,100,105,110,115dB were observed. Results The percentage of fetal movement evoked by 95dB airborne sound was 15% and was not significantly different from that of the controls. These percentages of fetal movement evoked by 100,105,110,115dB airborne sound were 89%, 83%, 83%, 95% respectively and were significantly higher than those in controls.The percentage of FHR deceleration evoked by 95dB airborne sound was 60% and significantly higher than that of control. These percentages of FHR acceleration evoked by 100,105,110 and 115dB airborne sound were 72%, 78%, 89%and 95% respectively and significantly higher than these of controls.These peak FHR amplitudes evoked by 95,100,105,110and115dB airborne sound were –4.5bpm, 12bpm, 17bpm, 14bpm and 20.5bpm respectively. Conclusion A subtle FHR deceleration and no fetal movement are evoked by 95dB airborne sound.FHR acceleration and fetal movement are evoked by 100～115dB airborne sound. It is suggested that 95dB airborne sound may induce fetal orientation reflex and 100～115dB may induce fetal defence reflex.These unconditional reflex of infant root from prenatal period.