Responses to vibroacoustic stimulation in a fetus with an encephalocele compared to responses of normal fetuses

Background: Observation of fetal movement and fetal heart rate (FHR) respon ses to repeated vibroacoustic stimulation (VAS) might be useful as a measur e to assess fetal well-being and to assess the integrity of the fetal centr al nervous system (CNS). We observed the movement and FHR responses to repe ated VAS of a term fetus with a serious brain anomaly as compared to respon ses of normal term fetuses. Subjects, methods, results: In 37 normal term fetuses and in a term fetus w ith an encephalocele we studied movement and FHR response to repeated VAS. All normal fetuses responded within 1 s after stimulation with general body movement and FMR acceleration. At 36 gestational weeks, no movement or FNR responses were seen in the fetus with an encephalocele. Repetition of the test in this fetus after one week still showed no response to repeated VAS. Conclusion: Normal fetuses showed movement and FHR responses to external st imulation. The fetus with an encephalocele did not respond to repeated VAS with a movement or FNR acceleration. Case studies in fetuses with structura l anomalies of the CNS are needed to gain insight into the spectrum of poss ible responses to VAS.