Fetal surveillance in diabetic pregnancy. II. The nonstress test versus the oxytocin challenge test.

Abstract

At the Department of Obstetrics and Gynecology, University of Lund, it has been the routine management in diabetic pregnancy to use both nonstress test (NST) and oxytocin challenge test (OCT) for fetal surveillance. The study material reported comprised 61 pregnant diabetics, 1,882 NSTs and 90 OCTs. Evaluations were made separately for the time interval 0-2 days antepartum, within 1 week antepartum, and all tests included. Predictive value, specificity and sensitivity were calculated for both the NSTs and the OCTs according to the following variables of neonatal outcome: Apgar scores at 1, 5 and 10 min, baby's first cry (or not) within 1 min of birth, pulmonary function, and metabolic balance. No perinatal deaths occurred. There were no statistically significant differences between the NSTs and OCTs in the antepartum time intervals 0-2 days and less than or equal to 1 week regarding any variable. When all tests were included, the OCT proved superior in that there were fewer falsely pathological tests, though biased by the fact that most of the NSTs evaluated were older than the oldest OCT in this context. Nevertheless, it is concluded that the OCT does not favor the NST for routine fetal surveillance in diabetic pregnancy.