Fetal surveillance in diabetic pregnancy. I. Predictive value of the nonstress test.

Abstract

Ninety-nine consecutive diabetic pregnancies (101 infants) were monitored with altogether 2672 nonstress tests (NSTs) from about 30 weeks of gestation until parturition. In 96% of the women the last NST was performed within 2 days of delivery. Fifty-nine percent had normal NSTs throughout pregnancy. Only 3.7% of the 2 672 tests were classified as pathological. When performed within 2 days antepartum, a normal NST predicted the 1-min Apgar score to be greater than or equal to 7 in 92%, and at 5 and 10 min in 99%. When all NSTs ever performed were included, the predictive value improved to 100%. The baby's first cry within 1 min after birth was predicted in 96%. Furthermore, the predictive value of a normal NST regarding the absence of ominous intrapartum cardiotocographic (CTG) patterns, normal pulmonary function and normal metabolic balance, was about 80%. The perinatal mortality was 1%. The specificity was in general good (86-96%), whereas the predictive value of pathological tests and the sensitivity almost without exception were poor. It is concluded that the very low rate of pathological NSTs indicates that obstetric interventions were made soon after the occurrence of the first sign of fetal jeopardy. Only then, and with meticulous care, is it possible to obtain good results. A normal NST is an excellent predictor of a normal Apgar score at 5 and 10 min, and also very good for a normal 1-min Apgar and an early cry from the baby. The predictive value is quite acceptable concerning the intrapartum CTG and the neonatal course likewise regarding the pulmonary function and metabolic balance.(ABSTRACT TRUNCATED AT 250 WORDS)