Revista de Biologia Neonatal

Abstrato

Fetal Response to Sound and Light: Possible Fetal Education?

Kazuo Maeda and Tatsumura M

Purpose: To assess fetal well-being and education ability by fetal response to sound and light. Material: Intrauterine fetuses in late pregnancy. Methods: The sound source was a loud speaker connected to an audioamplifier, of which source was sine waves, generated in a stimulator. The sound power was measured by an audiometer. The loud speaker was placed at the pregnant abdomen. A photographic speed light, of which guide number was 25, was flushed at pregnant abdomen around at fetal face, in the photic stimulation. Results: Acoustic and visual stimulation effects were fetal movements and heart rate (FHR) acceleration in fetal actocardiogram. The stimulation with 1,000 Hz 80 decibel (dB) sound for 2 S produced positive effects at 28 weeks, while 60 dB sounds achieved positive effects in 40 weeks, namely, sound sensitivity increased 10 folds in late pregnancy. Although foetuses responded to 250 and 500 Hz sound in 28 and 40 weeks, sound intensity reduction was insignificant. Positive results to photic stimulation were noted in 23 or later weeks and 77% cases achieved positive results in 40 weeks. Discussion: Positive effect of sound and light stimulation was fetal movements and FHR acceleration, which were the sign of healthy fetal brain, while, significant sound power reduction was noted only in 1,000 Hz, higher frequency than maternal voice, thus, fetal education will not be expected, and mother voice should be changed to 1,000 Hz using a voice changer in fetal education, however, healthy fetal hearing is expected by the response to 250-1,000 Hz sound and the response to flush light is the sign of healthy fetal retina and light sensing.