Nonreactive Nonstress Test Research Articles

An evaluation of antenatal fetal acoustic stimulation

Fetal heart rate reactivity was evaluated following acoustic stimulation testing (AST). The AST and NST (non-stress test) were compared with regards to certain adverse perinatal outcome criteria, and in a selected sample of cases, to other surveillance tests. These tests were the oxytocin challenge test (OCT) and biophysical profile (BPP). 479 tests were performed on 240 high-risk patients. The AST significantly increased fetal heart rate reactivity. With regards adverse perinatal outcome criteria, there was no significant difference between the AST and NST in relation to sensitivity, specificity or predictive values. In the 38 patients with both non-reactive NSTs and reactive ASTs, 5 (13.5%) had immediate follow-up surveillance tests (OCTs and/or BPPs) that were non-reassuring and necessitated delivery. In four of the five cases, there was evidence of potential fetal compromise. These preliminary observations suggest that the AST may have evoked reactivity in fetuses with early compromise, and raise concerns about replacing the NST with the AST as a primary screening test of fetal well-being.

Determinants of perinatal outcome in pregnancy-induced hypertension with absence of umbilical artery end-diastolic frequencies

Forty-three pregnancies that were complicated by pregnancy-induced hypertension and either absence of umbilical artery end-diastolic frequencies (n = 32) or reversal of umbilical artery end-diastolic frequencies (n = 11) were reviewed. The incidence of perinatal mortality and morbidity was similar for the two Doppler patterns. Perinatal survival was highly dependent on the gestational age when hypertension first appeared. Presentation at greater than or equal to 30 weeks' gestation was associated with a perinatal survival rate of 86%. Presentation at less than 30 weeks' gestation was associated with a perinatal survival rate of 38% (p less than 0.005). Pregnancy-induced hypertension that presented before 30 weeks was more often associated with a 5-minute Apgar score less than 7 (p less than 0.005) and a nonreactive nonstress test (p less than 0.05) compared with pregnancy-induced hypertension that presented at or beyond 30 weeks. For pregnancies that presented before 30 weeks, the only difference between perinatal survivors (n = 11) and perinatal deaths (n = 18) was a higher incidence of birth weight at or below the 10th percentile among deaths (p = 0.02).

Can the Nonstress Test Predict Congenital Sepsis?

The possible role of the nonstress test (NST) in the prediction of congenital sepsis in pregnancies complicated by prolonged premature rupture of the membranes (PROM) was investigated in a retrospective controlled study. Thirteen NSTs performed within 24 hours of the delivery of infants with congenital sepsis were coded, blinded, and mixed with an equal number of blinded NSTs derived from randomly selected patients matched for gestational age with PROM but without neonatal or maternal infection. Eleven of 13 infants with congenital sepsis had a reactive NST, and two had a nonreactive test. Among the controls, there were also 11 reactive and two nonreactive NSTs. The sensitivity and specificity of the NST in predicting congenital sepsis in patients with PROM were 15.4% and 84.6%, respectively. The positive predictive value and the negative predictive value were 50%. Our results suggest that the NST is not a useful tool for prediction of congenital sepsis.

Auscultated fetal heart rate accelerations: An alternative to the nonstress test

This nonexperimental, descriptive correlational study was conducted to determine whether a significant difference exists between the results of an electronically monitored nonstress test (NST) and those of auscultation for single fetal heart rate acceleration, the auscultated acceleration test (AAT). Of 130 NSTs, both the NST and the AAT were reactive in 105 cases and both were nonreactive in seven cases. Eighteen nonreactive AATs went on to have reactive NSTs (72.00% false-positive rate). There were no reactive AATs that went on to have nonreactive NSTs (0% false-negative rate). Various recommendations are made for future research in an attempt to decrease the false-positive rate. The McNemar's test for data analysis used in previous research indicated that there was a significant difference between the two tests. However, the sensitivity (100%) and specificity (85.37%) of the AAT indicate that the test is valid in predicting the results of the NST and thus appears to be a valid screening tool for fetal well-being and may be a reliable alternative to the NST.

Gram stain results from amniocentesis in patients with preterm premature rupture of membranes—Comparison of maternal and fetal characteristics

A total of 108 patients with preterm premature rupture of membranes who had undergone amniocentesis were retrospecively analyzed. Seventy-seven patients had negative amniotic fluid Gram stains and were managed expectantly. Thirty-one patients had positive amniotic fluid Gram stains confirmed by subsequent cultures and were delivered of infants on that basis. A univariate comparison of various parameters revealed significant differences in maternal temperature, pulse, and white blood cell count. Patients with positive Gram stains had lower mean gestational age, higher baseline fetal heart rate, and nonreactive fetal heart rate tracings. On the basis of a multivariate stepwise discriminate analysis, fetal heart rate >150 beats/min or nonreactive nonstress test were the best predictors of the Gram stain findings, with a sensitivity of 71 %, specificity of 76%, and negative predictive value of 87%. These data suggest that in patients with preterm premature rupture of membranes and fetal tachycardia or nonreactive nonstress test, amniocentesis should be performed in the initial evaluation.

The effect of magnesium sulfate tocolysis on the fetal biophysical profile

Abstract The biophysical profile has proved to be a valuable tool for the assessment of fetal well-being, independent of gestational age. Magnesium sulfate is commonly used as a tocolytic agent, yet relatively little is known about its effects on the biophysical activities of the fetus. To investigate the effects of magnesium sulfate on the biophysical profile, we performed serial studies on patients who received tocolytic therapy with this agent because of preterm labor. A total of 16 women with 22 fetuses at 26 to 34 weeks' gestation in spontaneous preterm labor were studied. An initial biophysical profile was performed at the time of admission, and a second examination was performed when maternal serum magnesium levels reached 6 to 8 mg/dl. On admission all fetuses had reactive nonstress test results and 21 of 22 (95%) demonstrated sustained fetal breathing movements. With magnesium sulfate tocolysis, 50% of fetuses had nonreactive nonstress test results, and only 4 of 22 (18%) demonstrated sustained fetal breathing movements. Fetal tone, gross body movements, and amniotic fluid volume were found to be unaffected by magnesium sulfate tocoysis. (Ann J OBSTET GYNECOL 1989;161:771-4.)

Übertragung: Pathophysiologie und Klinik

The postdate pregnancy remains an unresolved clinical problem with the threat of medicolegal consequences in cases of unfavorable outcome. Placental dysfunction leading to fetal hypoxia may develop in these pregnancies at any time and for the truly postmature fetus there is a considerable risk of asphyxia. Fetal hypoxia, accompanied with hemoconcentration due to a maternofetal fluid imbalance, leads to diminished fetal urine production and a reduced amniotic fluid volume, which can cause cord compression. According to this simplified pathophysiological cascade, the monitoring of postdate pregnancies should be based mainly on ultrasound assessment of amniotic fluid volume and cardiotocography. At our institution, instead of an obligatory induction of labor at a fixed gestational age, induction is performed when the largest amniotic fluid pocket measures less than 3 cm (vertical) or when variable decelerations of the fetal heart rate appear. A nonreactive nonstress test calls for a complete biophysical profile. As long as these monitoring techniques indicate fetal well-being, pregnancy is allowed to continue, especially in the presence of an incompatible condition of the cervix.

The effect of vibroacoustic stimulation on the nonstress test at gestational ages of thirty-two weeks or less

The effect of vibroacoustic stimulation on the nonstress test at gestational ages of less than or equal to 32 weeks was studied in 15 patients who underwent a total of 316 nonstress tests starting at 20 to 25 weeks' gestation. There were 168 nonreactive nonstress tests that were followed by 3 seconds of vibroacoustic stimulation. The incidence of reactive nonstress tests after vibroacoustic stimulation was significantly increased after 26 weeks' gestation. This may have clinical applicability and may be related to functional maturation of the fetal auditory system.

The effect of magnesium sulfate tocolysis on the fetal biophysical profile

The biophysical profile has proved to be a valuable tool for the assessment of fetal well-being, independent of gestational age. Magnesium sulfate is commonly used as a tocolytic agent, yet relatively little is known about its effects on the biophysical activities of the fetus. To investigate the effects of magnesium sulfate on the biophysical profile, we performed serial studies on patients who received tocolytic therapy with this agent because of preterm labor. A total of 16 women with 22 fetuses at 26 to 34 weeks' gestation in spontaneous preterm labor were studied. An initial biophysical profile was performed at the time of admission, and a second examination was performed when maternal serum magnesium levels reached 6 to 8 mg/dl. On admission all fetuses had reactive nonstress test results and 21 of 22 (95%) demonstrated sustained fetal breathing movements. With magnesium sulfate tocolysis, 50% of fetuses had nonreactive nonstress test results, and only 4 of 22 (18%) demonstrated sustained fetal breathing movements. Fetal tone, gross body movements, and amniotic fluid volume were found to be unaffected by magnesium sulfate tocoysis. (Ann J OBSTET GYNECOL 1989;161:771-4.)

Relationship between cyclic variation of fetal heart rate patterns and cord pH in preterm gestations.

The presence or absence of cyclic variation (cyclicity) of fetal heart rate patterns was prospectively investigated in fetuses between 25 and 32 weeks' gestation. All fetuses were delivered by cesarean section before the onset of labor. The relationship between the presence or absence of fetal heart rate cyclicity and fetal acidosis, as determined by cord pH measurements, was investigated. The sensitivity, specificity, positive predictive value, and negative predictive value of this method in predicting fetal acidosis were: 100, 90, 50, and 100%, respectively. All fetuses with reactive nonstress tests also had fetal heart rate cyclicity present and none were acidotic at birth. The majority of fetuses (68.8%) with nonreactive nonstress tests had fetal heart rate cyclicity present and none were acidotic; fetuses with nonreactive nonstress tests and absence of fetal heart rate cyclicity were acidotic in 50% of the cases. These preliminary data suggest that the presence or absence of fetal heart rate cyclicity may help to select the healthy preterm fetuses with nonreactive nonstress testing who are in good condition and therefore in no need for further testing.

Reevaluation of Nonstress Test by Umbilical Venous Blood Profile Using Cordocentesis

Fetal blood sampling by cordocentesis was performed in 85 cases of fetuses with either nonimmune hydrops fetalis, anomalies, intrauterine growth retardation, maternal immunological disorders, Rh incompatibility, hydronephrosis, polyhydramnios, maternal preeclampsia or fetal tumor. Fetal heart rate monitoring was also recorded before cordocentesis. We evaluated the usefulness of the nonstress test (NST) with regard to fetal hematologic gas profiles including pH, pO2 and pCO2. When the acceleration was classified into reactive and nonreactive group, pH and pO2 were significantly higher in the reactive group than in the nonreactive group. pCO2 was significantly lower in the former than the latter. However, the sensitivity and specificity of the reactive NST predicting fetal umbilical venous pO2 over 20 mm Hg was 79.7 and 68.7%, respectively. The false-positive rate of nonreactive NST predicting hypoxemia below 20 mm Hg pO2 was 44%. As a consequence, we cannot always rely on the NST, and should perform fetal blood sampling to assess fetal condition for further management.

The Four-Quadrant Assessment of Amniotic Fluid Volume: An Adjunct to Antepartum Fetal Heart Rate Testing

Amniotic fluid volume assessment using a semiquantitative four-quadrant technique, the amniotic fluid index, was evaluated in relationship to fetal heart rate (FHR) testing and perinatal morbidity in 330 high-risk pregnancies. An inverse relationship was found between the amniotic fluid index and nonreactive nonstress tests (NST), FHR decelerations, meconium staining, cesarean section for fetal distress, and low Apgar scores. More important, adverse perinatal outcome was significantly more frequent with diminished compared with normal amniotic fluid volume, even if the NST was reactive.

Correlation of Cerebral Function Monitoring with Non-Reactive Non-Stress Test

Correlation of Cerebral Function Monitoring with Non-Reactive Non-Stress Test

Correlation of Cerebral Function Monitoring with Non‐Reactive Non‐Stress Test

The cerebral function monitor, a system which records integrated electroencephalograms, was used to assess neurological status of newborns who had a non-reactive non-stress test prior to delivery. Babies born within 24 h of a non-reactive tracing had a significant lack of sleep cycling and persistence of immature patterns when compared with controls matched for gestational age.

Breast stimulation test and oxytocin challenge test in fetal surveillance: A prospective randomized study

Fifty healthy gravidas with uncomplicated singleton pregnancies at a gestational age of 35 to 42 weeks were assigned at random for the performance of either a breast stimulation test or an oxytocin challenge test after a nonreactive nonstress test. A satisfactory contraction stress test was achieved in 21 of 25 women in the breast stimulation test group and in 24 of 25 women in the oxytocin challenge test group (nonsignificant difference). Significant differences were found in the cumulative rate of achieved contraction stress tests: in the breast stimulation test group 17 of 21 after 20 minutes and 21 of 21 at 50 minutes whereas in the oxytocin challenge test group only four of 24 at 20 minutes, eight of 24 at 50 minutes, and 21 of 24 at 150 minutes. The mean duration for the achievement of a contraction stress test was 20.9 +/- 11.5 minutes for the breast stimulation test group and 81.3 +/- 48.4 minutes in the oxytocin challenge test group. Uterine hyperstimulation occurred once in each group. No gravida went into labor within 24 hours. Breast stimulation test is a satisfactory alternative to the oxytocin challenge test, is less time-consuming, and is simpler to perform.

Maternal response to daily fetal movement counting in primary care settings.

Maternal counting of fetal movement (FM) to assess fetal well-being was studied in 394 pregnancies followed by family physicians. Counting was well accepted, with 85% of women finding it reassuring and 91% wanting to include it in subsequent pregnancies. Eighty-eight percent of women reported counting five or more days per week. Thirteen women reported decreased activity a total of 20 times. A nonstress test (NST) was performed 20 times and an oxytocin challenge test (OCT) was performed four times as a result of these reports. One of the 20 reports of decreased activity was followed by a nonreactive NST and suspicious OCT, and led to the induction of a viable 38-week fetus. There were no stillbirths in the group and only one neonatal death of an anencephalic infant.

The relationships among the fetal biophysical profile, umbilical cord pH, and Apgar scores

The relationships among the fetal biophysical profile, umbilical cord blood pH, and Apgar scores were investigated in 124 patients undergoing cesarean section before the onset of labor. Based on a standard for the diagnosis of fetal acidosis of an umbilical cord arterial pH less than 7.20, the sensitivity, specificity, and positive and negative predictive values of the fetal biophysical profile score were 90%, 96%, 82%, and 98%, respectively. When the combination of a nonreactive nonstress test and absent fetal breathing was used as the "abnormal test," the sensitivity, specificity, and positive and negative predictive values were 100%, 92%, 71%, and 100%, respectively. The efficacy of the fetal biophysical profile to indicate fetal acidosis was found to be superior to the 1- and 5-minute Apgar scores in sensitivity and positive predictive value. These data suggest that the biophysical profile is very accurate in the identification of the fetus with acidemia. The first manifestations of fetal acidosis are nonreactive nonstress testing and loss of fetal breathing; in advanced acidemia fetal movements and fetal tone are compromised. A new protocol of antepartum fetal evaluation is suggested based on individual biophysical components rather than the score alone.

The use of fetal biophysical profile improves pregnancy outcome in premature rupture of the membranes

A protocol using daily fetal biophysical assessment was applied in 73 consecutive patients with premature rupture of the membranes and no clinical signs of infection or labor. A persistently low biophysical score (7 or less on two examinations 2 hours apart) in the presence of a nonreactive nonstress test and absence of fetal breathing was used as an indication for delivery. Measures of pregnancy outcome included the presence of amnionitis or neonatal infection. The outcome of pregnancy in this group of patients was compared with the outcomes of two historic groups: one managed conservatively (control group) and the other managed with amniocentesis on admission to the hospital (amniocentesis group). Infection outcome, maternal as well as neonatal, and low 5-minute Apgar scores were significantly less in the study than in the control group. The frequency of neonatal sepsis was significantly less in the study than in the amniocentesis group. These data suggest that management of premature rupture of the membranes with daily fetal biophysical profiles improves pregnancy outcome by reducing the incidence of maternal and neonatal infection.

Nonstress test and maternal position.

Antepartum evaluation of 225 low-risk primipara and 262 high-risk primipara and multipara using nonstress testing revealed 53 to be nonreactive when the test was performed in the supine position. When the test was repeated in the lateral decubitus position, it became reactive nonstress testing in 21 of these patients. This group of patients with a supine nonreactive nonstress test and a lateral reactive nonstress test demonstrated an associated compression of the abdominal aorta by the pregnant uterus in the supine, but not the lateral position. This study distinguishes three types of nonreactive nonstress tests: those due to placental insufficiency, those resulting from compression of the abdominal aorta by the pregnant uterus, and the falsely nonreactive. The percentage of false nonreactive nonstress tests results will be reduced by performing the test in the lateral decubitus position.

Monitoring of pregnancy in diabetes mellitus

From 1970-1984 116 diabetic pregnant patients were monitored and delivered at the University Hospital of Freiburg, Department of Obstetrics and Gynaecology. The pregnant diabetics were managed and controlled by an interdisciplinary team of internists and obstetricians. For better control of the maternal metabolic status, the diabetic patients were admitted to the hospital three times during their pregnancy. Foetal monitoring was done by ultrasonography, hormone analyses and cardiotocography. In most cases foetal growth retardation and macrosomia were detected early via sonography. Decreased urinary excretion of total oestrogen was measured during late pregnancy in 13% of the diabetic patients. In cardiotocography a loss of foetal reactivity was observed in 11% of all non-stress tests (NST). In more than 50% of these cases, the total oestrogen excretion also decreased. In patients with normal oestrogen values, an abnormal NST was rarely observed. Abnormal oxytocin challenge tests (OCT) were recorded in 19% of the patients. Among these cases most of the patients with a non-reactive NST were found. In 85% of the patients with pathological changes in the OCT a Caesarean section had to be performed, and among these in all patients with a loss of foetal reactivity in the cardiotocogram. In correlation with the foetal outcome, loss of reactivity in the cardiotocogram has greater pathological relevance than deceleration with maintenance of reactivity. For an early recognition of imminent placental insufficiency, OCT proved to be the most sensitive parameter. The increased incidence of acute placental insufficiency in diabetics during delivery underlines the need for repeated stress tests during late pregnancy.