Non-Stress Test Diagnostic Values for Predicting Fetal Outcomes in High Risk Pregnancies

Regarding the importance of having healthy child, there are several tests for fetal status assessment. Non stress testing is the most widely used primary testing method for assessment of fetal well-being in many researches but the predictability of the test is variable in different studies. Present study was designed to determine diagnostic values of the non-stress test for predicting fetal outcomes in high risk pregnancies 37-41 weeks. This study was performed retrospectively and reviewed two hundred and fifty high-risk cases include (pregnancy- induced hypertension, diabetes mellitus, oligohydramnios, premature rupture of membranes, decreased fetal movement, intrauterine growth restriction) in Dezyani hospital that performed non-stress testing before delivery and after reanalysis of test. We followed this parameters: decrease fetal heart rate during delivery, one and five minute apgar scores, need to resuscitation, NICU admission, meconium passage and fetal death. With respect of reactive and non-reactive response divided into two groups and based on occurrence of fetal complications after delivery compared between them. In this way sensitivity, specificity, positive predictive value, negative predictive value, Yuden index and accuracy of the test were estimated. We found that sensitivity, specificity, positive predictive value, negative predictive value, Yuden index and accuracy of the non-stress test for predicting fetal outcomes in high-risk cases were 43.2%, 74.7%, 48.1%, 71%, 17.9% and 63.6%. The frequency of low apgar, need to resuscitation and NICU admission were more common in the group of pregnancies with a non reactive NST than in the group with reactive NST. The difference was statistically significant (p<0.05). Reactive non-stress test is a good predictor of the healthy fetus, but non-reactive non-stress test is not valid.