Paula Broussard

Antepartum fetal heart rate testing

Abstract Antepartum fetal heart rate testing (AFHRT) was utilized in the assessment of fetal status on a large clinical service. The nonstress test (NST) was used as the primary approach. The contraction stress test (CST) was used in the face of persistent nonreactivity. The significance of fetal bradycardia occurring during AFHRT was assessed. Bradycardia was defined as a fetal heart rate (FHR) of 90 bpm or a reduction in FHR of 40 bpm below baseline, for 60 seconds or greater. In a 2-year period, there were 28 cases of bradycardia during 3,754 tests. A total of 24 cases were sent for delivery on the same day while four cases were managed in variable fashion. In 16 cases the tests were classified as nonreactive (abnormal) and the patients were sent for delifery on the same day. There was a 50% incidence of emergency delivery for fetal distress in labor in this group. In eight cases the tests were classified as reactive (normal) and the patients were sent for delivery on the same day. The incidence of fetal distress in labor with emergency delivery was 50%. Five of 10 patients with decreased amniotic fluid volume either on ultrasonic evaluation or by clinical estimation developed fetal distress in labor. There were three cases of congenital anomalies and one case of intrauterine growth retardation which exhibited diminished amniotic fluid. The occurrence of fetal bradycardia during AFHRT denotes a fetus at increased risk of developing fetal distress in labor. This type of test should be considered abnormal and consideration should be given to delivery of the fetus.

Fetal acoustic stimulation testing: II. A randomized clinical comparison with the nonstress test

Antepartum fetal heart rate testing, specifically the nonstress test, is of accepted value in the antenatal surveillance of high-risk pregnancies. Fetal rest-activity cycles coupled with arbitrary test intervals appear to lead to falsely nonreactive tests. Methods to alter fetal behavioral states have not been uniformly successful. A retrospective analysis of the adjunctive use of acoustic stimulation at our institution demonstrated a 50% reduction in the number of nonreactive tests. Consequently a prospective randomized clinical trial was undertaken to compare the standard nonstress test with the fetal acoustic stimulation test. Those patients randomized to the fetal acoustic stimulation test underwent transabdominal acoustic stimulation with a Model 5C electronic artificial larynx. The incidence of nonreactive tests was 14% in the control group and 9% in the study group (chi 2 = 11.09, p = 0.004). A significant reduction in testing time was also observed. The fetal acoustic stimulation test offers advantages over the traditional nonstress test by lowering the incidence of nonreactive tests and reducing testing time.

The role of ultrasound assessment of amniotic fluid volume in the management of the postdate pregnancy

Antepartum assessments of amniotic fluid volumes and their relationship to nonstress test patterns and pregnancy outcomes were retrospectively analyzed in 234 postdate pregnancies. The incidence of clinical oligohydramnios and a nonstress test revealing fetal heart rate deceleration or bradycardia was found to increase as the sonographic estimates of the amniotic fluid volume decreased. Furthermore, the postdate pregnancy with sonographic evidence of an adequate amniotic fluid volume had a significantly better perinatal outcome than the pregnancy without an adequate fluid volume. These results suggest that the postdate pregnancy with evidence of reduced amniotic fluid volume should be considered for a trial of labor with continuous electronic fetal monitoring.

Fetal acoustic stimulation testing: a retrospective experience with the fetal acoustic stimulation test.

The nonstress test is of accepted value in the surveillance of high-risk pregnancies. In order to improve the efficiency of testing, the authors retrospectively evaluated the adjunctive use of acoustic stimulation testing (FAS-TEST) in 1241 patients who underwent 3464 antepartum fetal heart rate tests. The results were compared to those in the previous 6 months during which time 1307 patients underwent 3573 nonstress tests. The frequency of nonreactive tests was 12.6% in the nonstress test group and 6.1% in those patients who underwent the FAS-TEST. The antepartum fetal death rates were not significantly different when the two groups were compared. The FAS-TEST decreases the percentage of nonreactive tests in a high-risk population and, as a consequence, may reduce the testing time.

The role of nonstress tests, fetal biophysical profile, and contraction stress tests in the outpatient management of insulin-requiring diabetic pregnancies

Antepartum fetal surveillance methods applicable in a home glucose-monitored population of pregnant diabetic women have been evaluated. A testing sequence of nonstress heart rate testing, backed up by either the fetal biophysical profile or contraction stress testing employed at a twice weekly interval, in 107 outpatients was compared with the management of 140 historic control patients by weekly nonstress tests and daily plasma estriols. There were 617 of 672 (91.8%) reactive nonstress tests in outpatients compared to 566 of 626 (90.4%) reactive tests in hospitalized control patients. Of 13 contraction stress tests performed in the outpatient group, only one was positive. Although 2,670 estriol determinations were done on hospitalized control patients, none was used for outpatients. No losses were attributed to unexplained antenatal stillbirth in either group. A fetal biophysical score of 8 was found to be at least as reliable as a reactive nonstress test. Antenatal surveillance in the well-controlled, insulin-requiring diabetic woman can be safely achieved with a testing sequence that consists of twice weekly nonstress tests backed up by the fetal biophysical profile and contraction stress tests.

Fifteen years of experience with antepartum fetal testing.

The introduction of antepartum fetal heart rate testing occurred in the very early 1970s. This article describes the evolution of testing within the Los Angeles County/University of Southern California Medical Center and encompasses a 15-year time period between 1971 and 1985. During this time approximately 200,000 patients were delivered of their infants. Fetal surveillance increased from less than 1% to current levels of 16% of patients. The antepartum fetal death rate was evaluated as a measure of evaluating the usefulness of antepartum testing. The fetal death rate after antepartum testing in selected high-risk patients was significantly less than that found in those patients not tested. The questions that might be raised regarding broader application of this technique and potential benefits are stated.

Antepartum fetal heart rate testing: XII. The effect of manual manipulation of the fetus on the nonstress test

A prospective study of 790 patients was performed in order to examine the role of manual manipulation of the fetus in the nonstress test. The patients were assigned randomly to two groups based on the last two digits of their hospital number. The odd-numbered patients underwent manual manipulation of the fetus prior to the onset of the nonstress test; the even-numbered patients did not. There was no significant difference between the two groups with respect to the indications for testing and the total number of tests. There was no statistically significant difference between the two groups with respect to the ratio of reactive to nonreactive nonstress tests and the mean duration of testing. Simple manual manipulation of the fetus does not seem to change the outcome in antepartum fetal heart rate testing when the nonstress test is the primary one.

Antepartum fetal heart rate testing: V. The nonstress test—an outpatient approach

A total of 567 tests were performed in a 1 year period on 399 patients in an outpatient clinic setting to test the feasibility of an office approach to antepartum heart rate testing. Of these tests, 510 were reactive and 57 were nonreactive (NR); 15 NR tests had associated spontaneous CSTs; 39 NR tests and one reactive test with an equivocal spontaneous CST were repeated in 2 to 4 hours; 30 tests were reactive and nine tests remained NR. An oxytocin-induced CST was needed to clarify fetal status in only nine of 607 tests. With this approach, the NST may be quite appropriate for office use.

Factors influencing nonstress test results in multiple gestations

The nonstress test remains the most widely used method of antepartum fetal health assessment in multiple gestations. However, few data are available on factors influencing its results in those cases. Our observation on 530 such tests has shown results similar to those in singleton gestations. Prematurity was associated with a higher rate of nonreactive tests; however, order and mode of presentation had no impact.