The prevalence of intra-uterine growth retardation in patients with positive contraction stress tests.

The gestational ages of 66 neonates delivered after positive contraction stress tests (CSTs) were estimated by means of the Dubowitz score. Forty-three (65%) of these infants had birth weights below the 10th percentile according to their gestational age. At the beginning of the study 40% of the infants were found to be growth-retarded, but as experience with antenatal fetal heart rate monitoring increased the CSTs were interpreted more accurately. This led to an increase in the incidence of IUGR in infants born after a positive CST to 82%, a predictive value which means that the test compares favourably with other methods of diagnosing the small-for-dates fetus.