Diagnostic Value of Non Stress Test in Latent Phase of Labor and Maternal and Fetal Outcomes

PURPOSE: The Non stress test (NST) is one of the significant diagnostic fetal wellbeing tests. The purpose of this study is to assess diagnostic value of NST during latent phase of labor by considering maternal and neonatal outcomes. SUBJECTS: This case control study was performed on 450 healthy pregnant women with gestational ages between 38-42 weeks in AL-Zahra teaching hospital in Tabriz, Iran. All participants underwent NST after being admitted to labor during their latent phase of delivery. Participants were divided into two groups including the study group which included 150 participants with non-reactive NST results whereas 300 subjects with reactive NST results assigned in the control group. Subjects in both groups were hospitalized for pregnancy termination because of the delivery time. In order to find out the importance of routine performance of NST during delivery, the relationship between NST results and maternal and fetal outcomes was evaluated. Several criteria including type of delivery, meconium defecation, descent arrest, bradycardia, Apgar score, and still birth were compared between two groups. RESULTS: Findings of this study showed that descent arrest occurred in 2.7% of the subjects in the study group, whereas it occurred in 4.7% of the participants in the control group (p=0.44). Bradycardia found in 28% of the participants in study group and 3.3% of the control group (p<0.001). The low Apgar score was found in 2.7% of case group however; no the low Apgar score detected in the control group. Meconium defecation observed in 11.3% of the subjects in the study group and 9.7% of the participants in control group (p=0.62). The amount of stillbirth was 2.7% in the study group and no stillbirths were found in control group. There was a significant difference between the results of both groups in terms of bradycardia, low Apgar score and cesarean section. CONCLUSION: Results of this study revealed that participants in study group with nonreactive NST results had more fetal complications than those with reactive NST results. NST was found to be a valuable diagnostic test for diagnosis of fetal distress during delivery in the latent phase. These findings of this study suggest that NST should be performed routinely as a valuable diagnostic test during the latent phase of delivery.