An assessment of the first decade's experience with antepartum fetal heart rate testing

The utility of antepartum fetal heart rate (APFHR) monitoring (nonstress test and the contraction stress test) was evaluated for a 10-year interval from 1974 through 1983. The number of high-risk patients evaluated increased from 2.9 to 25.1% of all deliveries. The decade's perinatal mortality rate differed from 22.4 per 1000 in the nontested population to 11.8 per 1000 in the tested population; the stillbirth rate differed from 11.1 per 1000 to 5.4 per 1000 uncorrected, 2.2 per 1000 corrected, and perinatal morbidity also differed from 26.1 per 1000 to 24.9 per 1000 (NS). Improvement statistics appear to plateau by the fourth year. An abnormal APFHR test was associated with a lethal congenital anomaly in 2.54% of patients (versus 0.5 to 1.5% in the general population). Evaluation for the presence of congenital anomalies appears to be indicated in the fetus with an abnormal APFHR test. A lower stillbirth rate occurred within 4 days of a normal APFHR test (0.027%) compared with a test interval of 5 to 7 days (0.11%). Thus, APFHR testing performed twice weekly may offer a better outcome for the fetus at risk than once weekly testing. This report confirms that the chief value of APFHR testing is its ability to identify the normal healthy fetus. These tests are somewhat less accurate at identification of the sick fetus. The nonstress test and contraction stress test were found to be of similar clinical predictive value.