RESUMO
The ability to evaluate fetal condition is of major importance to those who provide health care to pregnant women. Several testing methods such as non- stress test, contraction stress test and fetal biophysical profile, are presently used in antepartum assessment of fetal well - being [Divon el al., 1985]. The effects of two types of standardized external sound stimuli [500 Hz and 1000 Hz each at 110 dB] were studied on the fetal wellbeing. Electronic fetal monitoring, biophysical profile and flow wave velocimetry were recorded before and after both stimuli. The present study showed no significant changes in basal fetal heart rate with both types. However there was a marked rise in amplitude of fetal heart beats after 500 Hz and a marked drop after 1000 Hz. Also there was significant decrease of frequency of heart beats after 1000 Hz more than that after 500 Hz. Loss of acceleration was also reported after 1000 Hz. Study of biophysical profile showed that there was a marked increase of breathing movements and fetal movements after 500 Hz, while axial fetal movement was markedly diminished after 1000 Hz stimulation. Doppler study recorded insignificant increase in S/D ratio after both types of sound stimulation