ABSTRACT
Background and Objectives: Non-stress test (NST) is one of the most widely used primary tests for the assessment of fetal well-being. It is a graphical recording of fetal heart activity and uterine contractions simultaneously and continuously when uterus is quiescent with fetal movements. It has been incorporated into biophysical profile system. It is simple, inexpensive, non-invasive, easily performed, and interpreted. Hence, it can be used to screen a large population as an outpatient department procedure. This study was done to observe the efficacy and diagnostic value of NST for antenatal surveillance and comparison of test results with mode of delivery and adverse perinatal outcome. Materials and Methods: A total of 100 high-risk (HR) pregnant women (study group – selected based on inclusion and exclusion criteria) and 100 low-risk (LR) pregnant women (control group) were randomly enrolled into study and followed up with NST from 32 weeks of gestation and repeated at appropriate intervals in cases of the HR group. Results: In the LR group, there was an increased incidence of intrapartum fetal death (IPFD), meconium-stained amniotic fluid (MSAF), and decreased liquor quantity in non-reactive (NR) subgroup compared to reactive NST (R-NST) subgroup. However, in the HR group, NR-NST was associated with significantly increased incidence of decreased liquor quantity, low Apgar score at 5 min of birth, and perinatal mortality compared to the R-NST subgroup. Although the statistical incidence of IPFD was not significant in the NR-NST subgroup compared to R-NST, it appeared clinically significant. MSAF incidence was not significant in these two NST result subgroups. Sensitivity, specificity, and negative predictive value of NST in the LR group were 100%, 81.8%, and 100%, respectively; likewise, in the HR group, they are 75%, 78.1%, and 98.7%, respectively, for perinatal mortality. Conclusion: NST is a valuable screening test for detecting fetal compromise in both HR and LR fetuses that may have a poor perinatal outcome. Predictive value of NST for perinatal mortality was higher in the LR group compared to the HR group though statistically was not significant.