Introduction: Non-stress test (NST) is one of the most common tools for assessment of fetal wellbeing that has reactive and non-reactive results. Although it is limited by a high rate of false-positive results. This study was aimed to evaluate the accordance of NST results stimulated by vibroacoustic and halogen light and biophysical profile (BPP).
Methods: This clinical trial was held in 2010 on 100 pregnant women referred to Mirza Koochak Khan Hospital for NST. In the cases of 20-minute non-reactive fetal heart rate pattern, women were allocated in vibroacoustic group (N=50, who received vibration from a standard fetal vibratory stimulator), and halogen light group (N=50, who received from a halogen light source.( In vibroacoustic group, a vibration stimulator with a frequency of 80 Hz for 3 seconds and in halogen light group, the halogen light source with a million candle power by a flashlight for 10 seconds were applied on the maternal abdomen and above the fetal head. Afterward, fetal heart rate was recorded. Stimulated NST results were compared with BPP results. Gathered data were analyzed by SPSS software version 18. P value less than 0.05 was considered statistically significant.
Results: Two study groups were similar in terms of demographic characteristics such as maternal age (p=0.425), gestational age (p=0.271), body mass index (p=0.205) educational level (p=0.736) and the non-stress test (p=0.053). No statistical significant difference was observed between them. 68 and 62 percent change of a non-reactive to reactive status was occurred in halogen light group and vibroacoustic group, respectively. Both groups had the same diagnostic values such as positive and negative predictive values, specificity, and sensitivity. There was no significant relation between stimulus NSTs and BPPs.
Conclusion: To improve the results of non-stress test, vibroacoustic and light stimulations can be used as an assistive method along with common NST. Since in most cases, despite the improved NST, a reliable biophysical profile score is obtained, non-reactive pattern followed by external stimulation indicates no fetal risk.