External vibratory acoustic stimulation near term: fetal heart rate and heart rate variability responses.
Twenty-five pregnant women between 36 and 40 weeks' gestational age were studied to examine effects of a 5-second external vibratory acoustic stimulus on the fetal heart rate and fetal heart rate variability. There was an immediate significant increase in the basal heart rate, which persisted for 1 hour after the stimulus, compared to that of the control subjects. There was also a significant increase in the total time during which accelerations occurred for the first 20 minutes after the stimulus. There were no changes in computer-derived indices of fetal heart rate variability. Maternal blood pressure and heart rate were not altered following vibratory acoustic stimulus. We hypothesize that external vibratory acoustic stimulus causes a change from a state of sleep to a state of wakefulness in near term healthy fetuses.
D000161:Acoustic Stimulation / Q000379:methods; D001794:Blood Pressure; D005260:Female; D006339:Heart Rate; D006340:Heart Rate, Fetal; D006801:Humans; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D012890:Sleep; D014851:Wakefulness