A study of fetal outcome in pregnancy beyond 40 weeks using fetal heart rate monitoring with nonstress test

Objectives: Postdate pregnancy is the most common indication for Antepartum fetal heart rate testing because of its increased perinatal morbidity and perinatal mortality. It has long been recognized that the risk of adverse fetal outcomes, such as stillbirth, meconium aspiration, asphyxia, and the dysmaturity syndrome, is increased as gestational age progresses beyond 42 weeks. Materials and Methods: 55 patients with pregnancy beyond 40 weeks attending antenatal out-patient department of the Rajiv Gandhi medical college in the period between October 2014 to march 2015 were included. In present study, patients were monitored with twice weekly NST. In those with either NST nonreactive, induction was done. Cases with normal results were monitored till 42 weeks when routine induction was done. Results: A reactive nonstress test in prolonged pregnancy has good negative predictive value – i.e. adverse outcomes are unlikely to occur in the setting of a reactive non-stress test – but that the positive predictive values are low. Out of 55 patients, 71.2% went into spontaneous labour and remaining were induced. Five were induced when they reached 42 weeks, remaining were induced for abnormal NST. LSCS was done in 9 Cases (60%) in induced group. There was high incidence of caesarean section in induction group as compared with those who went into spontaneous labour. Out of 55 patients, 33 delivered vaginally (60%) of which most (50.9%) had spontaneous vaginal delivery. In three patients forceps was applied for prolonged second stage and in two patients prophylactic forceps for previous LSCS. Caesarean section was done in 22 patients (40%). Three were elective LSCS, one for breech presentation and two for previous LSCS. Most common indications for caesarean section were fetal distress (12 cases) and failure to progress (7cases) Of 72 NST, performed on 55 patients, 16 (22.3%) were nonreactive and 56(77.7%) were reactive. Reactive NST is reassuring and indicates fetal wellbeing. butnon reactive NST alone cannot be taken as an indicator of fetal jeopardy. The sensitivity and specificity of NST is 60% and 82.5% for Apgar<7 at 5 minute, 66.6%and 78.2% for NICU admission, 55% and 82.5% for Apgar<7 at 5 minute, 66.6% and 78.2% for NICU admission, 55% and 85.7% for meconium staining respectively. NST reactivity is statistically significant in predicting Apgar>7 at 5 minute, necessity of NICU admission and meconium passage. Conclusion: Reactive NST is reassuring and indicates fetal wellbeing, but non reactive NST alone cannot be taken as an indicator of fetal jeopardy. Although individual randomized trials do not show significant differences in perinatal mortality between women electively induced at specific gestational ages and women followed with antepartum testing, data shows significant increase in abnormal fetal outcome after 41 weeks.The presence FHR decelerations during and NST was associated with a less favourable outcome for the fetus.