Abstract Background: Vibroacoustic stimulator provokes a physiological sympathetic range response characterized by fetal heart rate acceleration suggesting an intact non-hypoxic CNS. Objectives: To assess the adjunctive use of vibroacoustic stimulation to alter fetal behavioral states, reduce the false positive non-reactive tests. Materials and Methods: A prospective study was conducted at Sri Adichunchanagiri institute of Health and Research Centre. 100 women performing VAST test and control group (n=100) without VAST test. It was done by placing vibroacoustic stimulator, with 75Db sound intensity at one meter, frequency of 75Hz on abdominal wall over fetal head for 3 seconds. Fetal startle response was observed along with fetal heart rate acceleration. If the test comes nonreactive, it is considered as positive test and if the test comes reactive it is considered as negative. Statistical Analysis: Chi-square test with descriptive and inferential statistical analysis was done. Summary and Results: With VAST, startle response was observed in 85% of patients in study group, 42 (89.4%) had normal perinatal outcome and 43(81.1%) had abnormal perinatal outcome. Association between BPP scoring before and after VAST was statistically significant(p<0.001). 85% of patients had reactive NST, 51(77.3%) had normal perinatal outcome and 34(100%) had abnormal perinatal outcome. Association between them were found to be statistically significant. Conclusion: It is simple, rapid and non- invasive tool for detection of fetal well being. VAST appears to be a safe and reliable method of antenatal fetal evaluation.
Keywords: VAST; NST; BPP.