Comparison of visual and computerized interpretation of nonstress test results in a randomized controlled trial. A randomized trial of weekly cardiotocography in high-risk obstetric patients. A randomized controlled trial of non-stress antepartum cardiotocography. Non-stress antenatal cardiotocography--a prospective randomized clinical trial. The value of antenatal cardiotocography in the management of high-risk pregnancy: a randomized controlled trial.
This study tested the null hypothesis that the number of fetal surveillance tests and perinatal outcomes would not differ statistically between pregnancies randomized to visual or computerized interpretation of antepartum nonstress test results.
                A prospective, randomized controlled trial was conducted, which required a sample size of 404 patients. By using a random-number table with assignment codes concealed in opaque envelopes, half of the patients were randomized to computerized interpretation of nonstress test results and half to standard visual interpretation of nonstress test results. The amount of antepartum testing and the perinatal outcome were measured and compared between the groups. Logistic regression analysis was used to control for maternal risk factors while morbidity differences between the 2 groups were assessed.
                The 2 randomized groups were similar at baseline, but the computerized interpretation group had significantly fewer biophysical profiles compared with the visual interpretation group (1.3 +/- 1.8 vs 1.9 +/- 2.1; P =.002). The patients in the computerized interpretation group spent less time per test than patients in the visual interpretation group (12 vs 20 minutes; P =.038). After the 5 pregnancies with congenital anomalies were excluded, the overall perinatal outcome was similar in the 2 groups. The computerized interpretation group, however, had a slightly lower proportion of infants who required >/=2 days of neonatal intensive care (7.4% vs 12.4%; P =.086; odds ratio, 0.56; 95% confidence interval, 0.29-1.09). The average number of neonatal intensive care days was also slightly lower in the computerized interpretation group (0.4 vs 0.9; P =.105). Neither of these variables was statistically significant.
                Computerized interpretation of nonstress test results is associated with fewer additional fetal surveillance examinations, less time spent in testing, and a similar length of stay in the neonatal intensive care unit compared with standard visual interpretation. A randomized clinical trial of once-weekly antenatal fetal heart rate monitoring in 539 high-risk patients could find no benefit of monitoring in terms of perinatal mortality, morbidity or Apgar score. The previously well-documented association between abnormal antenatal fetal heart rate traces and low Apgar score was confirmed. A detailed case review showed that in this population monitoring was irrelevant to almost all of the 13 perinatal deaths. In a prospective randomized controlled study of non-stress antepartum cardiotocography (CTG), involving 569 tracings in 300 patients, "non-reactive' traces showed a significant association with still-births and neonatal deaths, intrauterine growth retardation, admission to special care baby unit for conditions associated with intrauterine hypoxia, and low Apgar scores at 1 and 5 min. The report of the CTG was made available to the clinician in 144 patients and withheld in 156 patients. With the report available, significantly more patients were allowed to continue their antenatal care as out-patients, and significantly more antenatal in-patients were allowed home. There were no other significant differences in management, or outcome in the two groups. A randomized controlled trial examined the effects of non-stress antepartum cardiotocography on obstetric management and assessed its usefulness as a diagnostic test of fetal compromise. Daily cardiotocograph recordings were made in 396 antenatal patients at increased risk of fetal compromise but were withheld from the clinicians responsible for care in half the cases. The frequency of intrapartum fetal distress and low Apgar score was similar in the two groups. The three normally-formed perinatal deaths all occurred in the revealed group but in only one case could earlier obstetric intervention have altered the outcome. Availability of non-stress cardiotocography was not associated with an increased rate of induction of labour or caesarean section. The value of routine regular antenatal cardiotocography (CTG) in the management of high-risk pregnancy was assessed in a prospective randomized controlled study of 353 patients. All patients had a weekly CTG trace during the last 6 weeks of pregnancy and according to the random allocation the tracings were concealed from, or available to, the clinicians. Other methods of assessing fetal welfare were available to both groups. There was no significant difference between the concealed and revealed groups in the timing and mode of delivery, birthweights, Apgar score and neonatal morbidity. No apparent effect from the routine use of antenatal CTG in high-risk pregnancy was shown.
There is no clear evidence that antenatal CTG improves perinatal outcome, but further studies focusing on the use of computerised CTG in specific populations of women with increased risk of complications are warranted.