Study of non-stress test as a screening tool in low risk pregnancies at term gestation

Abstract

Introduction: Various antepartum surveillance method aim at early detection of fetal distress preventing intrauterine fetal death. Non Stress Test is one such tool used for screening antenatal patients. In this study non stress test is used to screen and monitor fetus of low risk mothers, to detect fetal distress take necessary intervention and correlate fetal outcome with test results. Materials and Method: This was a prospective longitudinal study conducted in Shalini Tai Meghe hospital and Research Centre, Wanadongiri, Nagpur from august 2019 till August 2020. 180 Antenatal patients with 37 completed weeks in labour and with no high risk factors were included in the study. Non Stress Test was performed on the patients and according to NICE guidelines, the result was interpreted as normal or abnormal. Results: Out of 180, 130 patients had normal Non-Stress Test and 46 patients had abnormal Non Stress Test. The percentage of normal delivery was 60.4% in normal non stress test group and 23.91% in abnormal non stress test group, where as the percentage of caesarean section was 33.58% in normal non stress test group and 63.04% in abnormal non stress test group. The most common indication for caesarean section in abnormal non stress test group was fetal distress with 68.96%. Meconium stained liquor was present in 73.91% patients with abnormal non stress test, with negative predictive value 72.34%, sensitivity 73.91% and specificity 72.34%. APGAR score < 7 at 5 minutes was present in 34.78% patients with abnormal non stress test group, with negative predictive value 81.36%, sensitivity 34.78% and specificity 97.76%. 18 babies from abnormal non stress test group were admitted in NICU with no perinatal mortality. Conclusion: Non stress test is a reliable screening tool for detecting high risk fetus in low risk mothers. The probability of adverse outcome like meconium stained liquor, low APGAR score, NISU admission increases with abnormal non stress test.