Purpose: To evaluate the significance of amniotic pocket (AP) measurements after 37 weeks of gestation for assessing the possibility of occurrence of non-reassuring fetal status (NRFS) during labor. Methods: The study population consisted of term patients (37-41 weeks of gestation) with singleton pregnancy, excluding admissions due to preterm rupture of membrane and for elective cesarean section (n=966). Subjects were divided into the following three groups; Group A: diagnosed as oligohydramnios during outpatient check-up, Group B: diagnosed as oligohydramnios at admission with onset of labor, and a control group. Frequencies of prompt delivery (emergent C/S or instrumental delivery) due to NRFS in each group were evaluated, and cutoff values of AP to predict prompt delivery were calculated. We also assessed sequential changes in AP before diagnosis of oligohydramnios. Results: The number of cases in Group A, Group B, and control were 26 (2.7%), 75 (7.8%), and 865 (89.5%), respectively. Frequencies of prompt delivery due to NRFS in Group A and B were 26.9% (p<0.001) and 16.0% (p=0.015), respectively, which were higher than control (7.9%). Frequencies of emergency cesarean section in Group A and control were 14.3% and 2.6%, respectively, and these were significant difference between them (p<0.001). A cutoff value of AP for predicting prompt delivery was calculated as 21 mm based on ROC curve. In the group diagnosed with oligohydramnios, AP was in the range of 20-30 mm 2 weeks and 1 week before the diagnosis in 65% and 83% of the cases, respectively. Conclusion: Measurement of AP is useful for predicting non-reassuring fetal status during labor in not only outpatients but also inpatients with onset of labor. Our results suggest that cases in which AP is less than 30 mm at outpatient check-up require intensive follow-up.