Background: The non-stress test is the most widely used test for the assessment of fetal health and reflects oxygenation of the brain. Fetal movements during testing are identified by maternal perception and are recorded. NST is based on the hypothesis that the heart rate of a fetus who is non-acidotic, non- impaired will temporarily accelerate in response to fetal movements. The fetal heart rate normally is increased or decreased by autonomic influences mediated by sympathetic or parasympathetic impulses from brain stem centers. NST uses minimum thresholds of FHR acceleration frequency to distinguish healthy from compromised fetuses. The value of “reactivity” or accelerations associated with fetal movement may vary considerably with the composition of the population tested, gestational age, the frequency of test repetition, and the use of other baseline FHR features in the evaluation of the test.
Methodology: The study was conducted at Department of OBGY in a tertiary care hospital in India for a duration of one year. 100 pregnant woman with pregnancy from 37 weeks to 42 weeks of gestation were included in the study. The electronic fetal monitor is used for NST. The NST was categorized as Reactive and Non -Reactive. Reactive In a 20-minute period, two or more fetal heart rate accelerations of at least 15 beats per minute above the baseline heart rate. If the NST came out to be non-reactive, NST was repeated for another 20 minutes and if it still remained Non- reactive then Biophysical profile was done for that patient and the decision was taken according to the result of the biophysical profile score.
Results: The mean age of patients was 26.72\(\pm\)4.58 years. Out of 100 NST, -67 (67%) NST were reactive while 23 (23.18%) were non-reactive. Women admitted with reactive NST had significantly higher vaginal delivery rates i.e. (42% vs. 14%). Operative delivery in non -reactive NST group was significantly higher than the reactive NST group, i.e., (86% vs. 58%). All 100 babies were born alive irrespective of the NST status and 13% (13) required NICU admission. The individual parameters of poor fetal outcome like meconium stained liquor, Apgar score <7 at 5 minutes had increased incidences in the non-reactive group.
Conclusion: The “NST at admission” is a straightforward and uncomplicated procedure for determining the fetal status antenatally. Its responsiveness ensures a positive outcome for both the mother and the fetus, while non-responsiveness raises the risk of operative delivery and NICU hospitalization.
