足月胎儿对声音刺激反应的探讨

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、100、105、110、115分贝的声音刺激，观察胎儿的胎动和胎心率反应。95分贝声音能引起胎心率轻度下降且不引起胎动，而声强在100分贝以上的声音刺激能引起胎心率加速并伴有胎动，提示95分贝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100~115分贝的声音能引起胎儿的防卫反应。婴儿与生俱来的无条件反射在胎儿期就已存在。

THE RESPONSES OF TERM FETUSES TO DIFFERENT ACOUSTIC STIMULATIONS

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 ⑴The 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. ⑵The 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. ⑶These 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.