Pathological Fetal Heart Rate Patterns Research Articles

Safety and efficacy of sildenafil citrate to reduce operative birth for intrapartum fetal compromise at term: a phase 2 randomized controlled trial

Sildenafil citrate is a vasodilator used in erectile dysfunction and pulmonary hypertension. We tested whether it reduces emergency operative births for fetal compromise and improves fetal or uteroplacental perfusion in labor in a phase 2 double-blind randomized controlled trial. Women at term in early labor or undergoing scheduled induction of labor at Mater Mother's Hospital, Brisbane, Australia, were randomly allocated 50 mg of sildenafil citrate orally 8hourly up to 150 mg or placebo. Intrapartum fetal monitoring followedRoyal Australian and New Zealand College of Obstetricians andGynaecologists guidelines. Primary outcomes were (1) emergency operative birth (by cesarean delivery or instrumental vaginal birth)forintrapartum fetal compromise and (2) mean indices of fetalanduteroplacental perfusion using Doppler ultrasound. Analysiswas by intention-to-treat. ANZCTRN12615000319572 RESULTS: Between September 2015 and January 2019, 300 women were randomized equally to sildenafil citrate or placebo. Sildenafil citrate reduced the risk of emergency operative birth by 51% (18% vs 36.7%; relative risk, 0.49, 95% confidence interval, 0.33-0.73, P=.0004, number needed to treat= 5 [3-11]). There was no difference in indices of fetal and uteroplacental perfusion, but these were ascertained in only 71 women. Sildenafil citrate reduced the risk of meconium-stained liquor or pathologic fetal heart rate patterns by 43% (25.3% vs 44.7%; relative risk, 0.57, 95% confidence interval, 0.41-0.79, P=.0005), but its effects on fetal scalp sampling rates (2.0% vs 6.7%; relative risk, 0.30, 95% confidence interval, 0.08-1.07, P=.06) and adverse neonatal outcome (20.7% vs 21.3%; relative risk, 0.97, 95% confidence interval, 0.62-1.50, P=.89) were inconclusive. Only 3.6% of maternal levels of sildenafil citrate or its metabolite were detected in cord blood. No differences in maternal adverse events were seen. Sildenafil citrate reduced operative birth for intrapartum fetal compromise, but much larger phase 3 trials of its effects on mother and child are needed before it can be routinely recommended.

Intrapartum and perinatal results associated with different degrees of staining of meconium stained amniotic fluid

ObjectiveTo determine the intrapartum and perinatal results associated with different degrees of staining of meconium stained amniotic fluid (MSAF). Study designIn a retrospective cohort study of all singleton deliveries over a period of one year (2015) in a tertiary hospital, we compared different degrees of MSAF (yellow, green and thick) to clear amniotic fluids, and analysed in each group maternal, intrapartum and neonatal variables as well as umbilical cord blood gas analysis. ResultsOf the 3590 deliveries included, 503 (14%) had MSAF. The incidence of MSAF rises with gestational age at delivery, reaching 20.7% in gestations above 41 weeks compared to 4.3% below 37 weeks. As the amniotic fluid staining progresses we found a higher proportion of intrapartum fevers (p < 0.001), pathological fetal heart rate patterns (p < 0.05), operative vaginal deliveries and cesarean sections (p < 0.001), as well as the need for advanced neonatal resuscitation (p < 0.001). There was also a correlation between MSAF and low Apgar scores at five minutes (p < 0.001) and fetal-neonatal mortality (p < 0.001) but there was not a higher proportion of neonatal intensive care admissions (p > 0.05). We have observed a similar distribution of umbilical artery pH ranges in all groups (p > 0.05). ConclusionsMSAF was associated with an increase in the rate of pathological fetal heart rate patterns, intrapartum fevers, operative vaginal and cesarean section deliveries, need for neonatal resuscitation, low Apgar scores and higher fetal-neonatal mortality. Moreover, we found that the risks increase as the staining and consistency of the amniotic fluid evolves so it should alert the obstetrician and paediatrician to the potential adverse outcomes.

Intrapartum and perinatal results associated with different degrees of staining of meconium stained amniotic fluid

ObjectiveTo determine the intrapartum and perinatal results associated with different degrees of staining of meconium stained amniotic fluid (MSAF). Study designIn a retrospective cohort study of all singleton deliveries over a period of one year (2015) in a tertiary hospital, we compared different degrees of MSAF (yellow, green and thick) to clear amniotic fluids, and analysed in each group maternal, intrapartum and neonatal variables as well as umbilical cord blood gas analysis. ResultsOf the 3590 deliveries included, 503 (14%) had MSAF. The incidence of MSAF rises with gestational age at delivery, reaching 20.7% in gestations above 41 weeks compared to 4.3% below 37 weeks. As the amniotic fluid staining progresses we found a higher proportion of intrapartum fevers (p < 0.001), pathological fetal heart rate patterns (p < 0.05), operative vaginal deliveries and cesarean sections (p < 0.001), as well as the need for advanced neonatal resuscitation (p < 0.001). There was also a correlation between MSAF and low Apgar scores at five minutes (p < 0.001) and fetal-neonatal mortality (p < 0.001) but there was not a higher proportion of neonatal intensive care admissions (p > 0.05). We have observed a similar distribution of umbilical artery pH ranges in all groups (p > 0.05). ConclusionsMSAF was associated with an increase in the rate of pathological fetal heart rate patterns, intrapartum fevers, operative vaginal and cesarean section deliveries, need for neonatal resuscitation, low Apgar scores and higher fetal-neonatal mortality. Moreover, we found that the risks increase as the staining and consistency of the amniotic fluid evolves so it should alert the obstetrician and paediatrician to the potential adverse outcomes.

Fetal heart rate patterns and neurodevelopmental outcome in very low birth weight infants

To evaluate the validity of fetal heart rate monitoring during the last hour prior to birth, as a predictor of long term neurodevelopmental outcome of very low birth weight infants. A total of 111 very low birth weight infants were included in the study. Fetal heart rate tracings were obtained during the last hour prior to delivery. A perinatologist, blinded to the neonatal outcome, evaluated the tracings and divided them into three groups: reassuring, nonreassuring, and pathological. Neurodevelopmental status was evaluated at age 2 years. The relationship between fetal heart rate monitoring results and the neurodevelopmental outcome at 2 years of age was assessed with a chi-square test and the Student's t-test. At 2 years of age 97 (87.4%) of the children had normal neurodevelopmental function, while 14 (12.6%) had variable degrees of neurodevelopmental impairment. The fetal heart rate monitoring results were classified as reassuring (normal) in 35 cases (31.5%), nonreassuring in 56 cases (50.5%), and pathological in 20 cases (18.0%). Both normal and pathological fetal heart rate patterns were associated with similar incidence of abnormal neurodevelopmental outcome, 14.3% and 15.0% of cases, respectively (p=0.778). Pathological fetal heart rate patterns as a predictor of neurodevelopmental outcome had a sensitivity of 27%, specificity of 74%, positive predictive value of 15%, and negative predictive value of 86%. Electronic fetal heart rate monitoring prior to delivery is not a reliable tool for the prediction of neurodevelopmental impairment in premature infants of very low birth weight, at 2 years of age.

Fetal heart rate patterns and neurodevelopmental outcome in very low birth weight infants

Background . To evaluate the validity of fetal heart rate monitoring during the last hour prior to birth, as a predictor of long term neurodevelopmental outcome of very low birth weight infants. Methods. A total of 111 very low birth weight infants were included in the study. Fetal heart rate tracings were obtained during the last hour prior to delivery. A perinatologist, blinded to the neonatal outcome, evaluated the tracings and divided them into three groups: reassuring, nonreassuring, and pathological. Neurodevelopmental status was evaluated at age 2 years. The relationship between fetal heart rate monitoring results and the neurodevelopmental outcome at 2 years of age was assessed with a chi-square test and the Student’s t-test. Results. At 2 years of age 97 (87.4%) of the children had normal neurodevelopmental function, while 14 (12.6%) had variable degrees of neurodevelopmental impairment. The fetal heart rate monitoring results were classified as reassuring (normal) in 35 cases (31.5%), nonreassuring in 56 cases (50.5%), and pathological in 20 cases (18.0%). Both normal and pathological fetal heart rate patterns were associated with similar incidence of abnormal neurodevelopmental outcome, 14.3% and 15.0% of cases, respectively (p /0.778). Pathological fetal heart rate patterns as a predictor of neurodevelopmental outcome had a sensitivity of 27%, specificity of 74%, positive predictive value of 15%, and negative predictive value of 86%. Conclusion. Electronic fetal heart rate monitoring prior to delivery is not a reliable tool for the prediction of neurodevelopmental impairment in premature infants of very low birth weight, at 2 years of age.

Oral misoprostol versus intracervical dinoprostone for induction of labor

Objectives: To compare oral misoprostol with dinoprostone for induction of labor and their effects on the fetal heart rate patterns. Methods: In a randomized controlled trial, 200 patients received either misoprostol 50 μg orally for every 4 h, or dinoprostone 0.5 mg intracervically for every 6 h. Cardiotocographic recordings, in 10-min windows 30, 60, and 80 min after prostaglandin administration during induction and continuously during labor, were compared between the two groups. Primary outcome for effectiveness and safety was assessed in terms of the number of vaginal deliveries within 24 h and fetal heart rate abnormalities during induction and labor respectively. Results: Data from 96 patients in the misoprostol group and 95 in the dinoprostone group were analyzed. There were no significant differences in respect of the number of vaginal deliveries within 24 h (RR 1.12; 95% CI 0.88–1.42). The frequency of suspicious and pathological fetal heart rate patterns did not differ significantly but significantly more cardiotocographs in the dinoprostone group had non-reassuring baseline variability 60 min after dose administration (RR 0.33; 95% CI 0.14–0.77). Maternal and neonatal outcomes did not differ significantly. Conclusion: Oral misoprostol is as effective as intracervical dinoprostone for induction of labor with no difference in the frequency of fetal heart rate abnormalities.

Abnormal fetal heart rate tracing patterns during the first stage of labor: Effect on perinatal outcome

Objective: The purpose of this study was to evaluate perinatal outcomes of infants who had pathologic fetal heart rate tracings during the first stage of labor, in comparison with pregnancies with normal tracings. Study Design: The perinatal outcomes of 301 infants born at 37 to 42 weeks of gestation with pathologic fetal heart rate patterns during the first stage of labor were compared with 300 infants with normal fetal heart rate tracing patterns. The data were collected prospectively. Tracings were interpreted with the use of the National Institute of Child Health and Human Development fetal heart rate monitor guidelines. Results: Hydramnios (odds ratio, 7.68; 95% CI, 1.75%-33.63%), oligohydramnios (odds ratio, 2.74; 95% CI, 1.01%-7.39%), and the presence of meconium-stained amniotic fluid (odds ratio, 1.91; 95% CI, 1.03%-3.3%) were independent factors that were associated with pathologic fetal heart rate monitoring during the first stage of labor in a multivariable analysis. The occurrences of umbilical arterial pH of <7.20, a 1-minute Apgar score of <7, a base deficit of 12 mmol/L or higher, and operative deliveries were significantly higher in the study group as compared with subjects with normal fetal heart rate monitoring. Late decelerations and severe variable decelerations (<70 bpm) during the first stage of labor were independent risk factors (odds ratio, 17.5; 95% CI, 1.61%-185.7% and odds ratio, 3.9; 95% CI, 1.36%-11.7%, respectively) that were associated with fetal acidosis (determined by both pH of <7.2 and a base deficit of 12 mmol/L or higher) in a multiple logistic model, controlled for hydramnios, oligohydramnios, meconium-stained amniotic fluid, augmentation by oxytocin, nulliparity, duration of first stage of labor, and birth weight. Conclusion: The operative delivery rate was higher among patients with abnormal first-stage fetal heart rate patterns. Late decelerations and severe variable decelerations were significant factors associated with fetal acidosis. (Am J Obstet Gynecol 2001;185: 863-8.)

Erfahrungen mit der Mamillenstimulation zur Weheninduktion

At the Gynaecological Department of the University of Innsbruck, 207 nipple stimulation for the induction of uterine contractions were performed, using the necessary precautions, in 186 pregnant women at term. The continuous or intermittent manual stimulation by the patient was mainly used for contraction stress testing. An adequate uterine response (at least 3 contractions per 10 minutes) was achieved in 57%. Reversible signs of hyperstimulation, such as prolonged uterine contractions and tachysystoles, were observed in 10%, causing reversible pathologic fetal heart rate patterns in 1%. The classical intravenous oxytocin challenge test produced a higher uterine response rate as compared at the same time to breast stimulation. Provided, that an adequate response was achieved, normal and pathological fetal reaction patterns were identical in both tests. In 20 patients we used nipple electrostimulation. Results were similar to those achieved by manual stimulation. Due to the conflicting reports in the literature and because of the potential hazards involved, the use of nipple stimulation for the induction of uterine contractions can be advocated only in a controlled clinical setting. Its application without medical supervision, as propagated in the lay press, is definitely contraindicated.

Prostaglandin E 2 gel for cervical ripening and induction of labor: A critical analysis

This report summarizes the cumulative experience of 3313 pregnancies represented in 59 prospective clinical trials in which intracervical or intravaginal prostaglandin E 2 gel was used for cervical ripening before induction of labor. Results indicate that local prostaglandin E 2 is superior to placebo or no therapy in enhancing cervical effacement and dilation, reducing initial induction failures, shortening the induction-delivery interval, reducing oxytocin use, and lowering the rate of cesarean section because of failure to progress. Certain advantages also exist for labor induction in the presence of a favorable cervical state. Uterine hyperstimulation or pathologic fetal heart rate patterns before oxytocin administration occur in 2 gel administered before induction of labor is of major therapeutic benefit and should become commercially available for more than investigational use.

Fetal heart rate patterns in red blood cell isoimmunized pregnancies

Fetal heart rate was monitored in 33 red blood cell isoimmunized patients at 32 to 36 weeks' gestation immediately before cordocentesis. The fetal heart rate patterns were analyzed according to 25 different classifications, and the values were related to the fetal hemoglobin concentration, oxygen tension, and oxygen content. Nonreactive, suboptimal, or pathologic fetal heart rate patterns were encountered more commonly in fetuses that were hypoxemic and anemic than in those that were normoxemic and nonanemic. However, the positive predictive value of these abnormal fetal heart rate patterns with respect to fetal anemia was 50% to 100%; the negative predictive value was 18% to 40%.

Heart rate patterns in normoxemic, hypoxemic, and anemic second-trimester fetuses

Fetal heart rate monitoring was performed immediately before cordocentesis on 71 occasions on 49 patients at 20 to 26 weeks' gestation. In the normoxemic, nonanemic fetuses, the basal fetal heart rate was 120 to 160 beats/minute, the baseline variability was more than 5 beats/min, and there were no prolonged decelerations. Accelerations were present in 19 of the 25 recordings. In the tracings from the hypoxemic (n = 11) or anemic (n = 35) fetuses, there was tachycardia, baseline variability of <5 beats/min, and prolonged fetal heart rate decelerations. However, the sensitivity of these pathologic patterns in predicting moderate-to-severe hypoxemia or anemia was 45% and 33%, respectively. The data demonstrate a gestation-dependent maturation of both normal and pathologic fetal heart rate patterns. (Ann J OBSTET GYNECOI. 1989;160:1034-7.)

Prostaglandin E 2 gel for cervical ripening and induction of labor: A critical analysis

This report summarizes the cumulative experience of 3313 pregnancies represented in 59 prospective clinical trials in which intracervical or intravaginal prostaglandin E2 gel was used for cervical ripening before induction of labor. Results indicate that local prostaglandin E2 is superior to placebo or no therapy in enhancing cervical effacement and dilation, reducing initial induction failures, shortening the induction-delivery interval, reducing oxytocin use, and lowering the rate of cesarean section because of failure to progress. Certain advantages also exist for labor induction in the presence of a favorable cervical state. Uterine hyperstimulation or pathologic fetal heart rate patterns before oxytocin administration occur in less than 1% of reported cases and are usually dose related, self contained, and reversible with the use of beta-adrenergic tocolytic therapy. Maternal systemic effects in these low doses are negligible. Worldwide clinical experience has clearly demonstrated that prostaglandin E2 gel administered before induction of labor is of major therapeutic benefit and should become commercially available for more than investigational use.

Alterations of Pathological Fetal Heart Rate Patterns in Labor following Vibroacoustic Stimulation

Vibroacoustic stimulation of the fetus in labor was previously shown to result in a transient fetal heart rate (FHR) tachycardia followed by a return to prestimulation FHR pattern. We presently report 3 cases in which FHR patterns of repeat decelerations were changed to normal following vibroacoustic stimulation. These changes may be related to the strong fetal movements evoked by the stimulation and removal thereby of a mechanical problem such as cord compression.

Intrapartum fetal heart rate monitoring in a combined low- and high-risk population: a controlled clinical trial

In a prospective clinical randomized investigation 487 women had the condition of the fetus during labour supervised by means of stethoscope (AUS), while 482 women went through labour under surveillance of electronic fetal monitoring, cardiotocography (EFM). 349 women refused to participate in the investigation (NAI) and had delivery conducted according to the normal procedures of the department (70% AUS, 30% EFM). Significantly more pathological fetal heart rate patterns (FHR) were found in the EFM group compared to the AUS group in both the first and the second stage of labour. As a result significantly more vacuum extractions were performed in the EFM group than in the AUS group, while no statistical difference was found between the groups in the incidence of acute cesarean sections carried out for asphyxia. One case of intrapartum death occurred in the AUS group. No differences were found in Apgar scores after 1 and 5 min or in neonatal morbidity at examination on the 2nd and 5th days after delivery. A tendency towards more biochemically compromised children was found in the AUS group. The specificity for both methods was found to be acceptably high (80%), while the predictive value for both methods was low (50%). More research is therefore urgently needed to evaluate supplementary investigations and parameters for the evaluation of the intrapartum fetal condition.

Fetal Heart Rate Patterns and Perinatal Outcome of Very-Low-Birthweight Infants

Summary. The obstetric records of 125 infants weighing 500–1250 g who were born in 1978 and 1979 at the Helsinki University Central Hospital were studied retrospectively to find out any associations between fetal heart rate (FHR) patterns and perinatal outcome. FHR recordings of 79 fetuses were available for study. Normal reactive patterns were observed in nine, nonreactive in 54, decelerations in 58, silent patterns in 45 and combined distress patterns in 36 fetuses. The interval from the first pathological sign to delivery was up to 27 days. Five fetuses in the monitored group died in utero, 26 infants died neonatally and two later. The risk of neonatal death after pathological FHR patterns was lower than after an FHR pattern without abnormality. Idiopathic respiratory distress syndrome (RDS) was diagnosed in 32 infants, of whom 16 died. Forty-seven fetuses (59%) of the monitored group were delivered abdominally and 32 vaginally. The risk of RDS was not significantly associated with FHR patterns and mode of delivery. We conclude that unlike term fetuses, low-birthweight fetuses seem to benefit from a period of intrauterine stress reflected in abnormal FHR patterns, if caesarean section is used liberally.

Fetal heart rate patterns and perinatal outcome of very-low-birthweight infants.

The obstetric records of 125 infants weighing 500-1250 g who were born in 1978 and 1979 at the Helsinki University Central Hospital were studied retrospectively to find out any associations between fetal heart rate (FHR) patterns and perinatal outcome. FHR recordings of 79 fetuses were available for study. Normal reactive patterns were observed in nine, nonreactive in 54, decelerations in 58, silent patterns in 45 and combined distress patterns in 36 fetuses. The interval from the first pathological sign to delivery was up to 27 days. Five fetuses in the monitored group died in utero, 26 infants died neonatally and two later. The risk of neonatal death after pathological FHR patterns was lower than after an FHR pattern without abnormality. Idiopathic respiratory distress syndrome (RDS) was diagnosed in 32 infants, of whom 16 died. Forty-seven fetuses (59%) of the monitored group were delivered abdominally and 32 vaginally. The risk of RDS was not significantly associated with FHR patterns and mode of delivery. We conclude that unlike term fetuses, low-birthweight fetuses seem to benefit from a period of intrauterine stress reflected in abnormal FHR patterns, if caesarean section is used liberally.

Is End-Stage Deceleration of the Fetal Heart Ominous?

Little information is available on the significance of the dramatic fall in fetal heart rate which may occur during the second stage of labor. Although the drop appears ominous, the newborn infant is usually in excellent condition. In the present study, an attempt is made to assess the significance of end-stage deceleration and to discuss the management of labor in such cases. During the period from January 1 to July 1, 1980, 3540 women gave birth in the authors' medical center, and 1593 (45 per cent) had continuous fetal heart rate monitoring in labor. End-stage deceleration was diagnosed in 55 (3.4 per cent) of those monitored. The average drop in baseline fetal heart rate during end-stage deceleration was 45.5 beats per minute (range, 20 to 90 beats per minute). Forty-nine of the infants had one-minute Apgar scores of 7 or more; the remaining six were depressed at delivery and had one-minute Apgar scores of 5 or less. In 49 patients who had healthy babies, the fetal heart rate pattern preceding deceleration was normal. In the six patients who gave birth to depressed babies, pathological fetal heart rate patterns were present before deceleration, although fetal scalp blood pH in early labor was within normal limits. In four of these six, fetal scalp blood was sampled again during end-stage deceleration, and the pH was significantly lower. Vacuum extractor or outlet forceps were used in five deliveries; the sixth fetus was delivered spontaneously 5 minutes after the onset of deceleration, severely depressed and acidotic. Umbilical vein pH values in all six babies were acidotic. No relation was found between the depth of drop in fetal heart rate or the duration of deceleration and fetal condition on delivery, provided the heart rate was normal until end-stage deceleration. When umbilical vein pH values were related to the duration of deceleration, however, it was shown that values dropped to pre-acidotic levels when deceleration had persisted for more than 15 minutes (P < 0.001). The mean pH was 7.27 when end-stage deceleration lasted 1 5 minutes or less and 7.23 if deceleration persisted for more than 1 5 minutes (P < 0.001). Umbilical vein pH and the one-minute Apgar score were less dependent on the mode of delivery than on fetal heart rate patterns during labor and the duration of deceleration. Fetal scalp blood pH during end-stage deceleration was obtained from 25 patients and compared with umbilical vein blood pH. A weak correlation between the two could be demonstrated (r = 0.354), but all four infants who had low fetal scalp blood pH values during deceleration also had preacidotic or acidotic umbilical vein blood pH values.

Is end-stage deceleration of the fetal heart ominous?

End-stage deceleration (ESD) defined as deep and sustained fetal bradycardia during the second stage of labour was observed in 55 patients. Fetal well-being and neonatal outcome were assessed with fetal-scalp pH, umbilical-vein pH and 1-min Apgar score values. Only six infants with pathological fetal heart-rate patterns before ESD had a 1-min Apgar score of less than 7 and an acidotic umbilical-vein pH. The remaining 49 babies were born in excellent condition, although when ESD persisted for more than 15 min umbilical-vein pH decreased.

8 - Obstructed Labour

To determine the intrapartum and perinatal results associated with different degrees of staining of meconium stained amniotic fluid (MSAF).In a retrospective cohort study of all singleton deliveries over a period of one year (2015) in a tertiary hospital, we compared different degrees of MSAF (yellow, green and thick) to clear amniotic fluids, and analysed in each group maternal, intrapartum and neonatal variables as well as umbilical cord blood gas analysis.Of the 3590 deliveries included, 503 (14%) had MSAF. The incidence of MSAF rises with gestational age at delivery, reaching 20.7% in gestations above 41 weeks compared to 4.3% below 37 weeks. As the amniotic fluid staining progresses we found a higher proportion of intrapartum fevers (p < 0.001), pathological fetal heart rate patterns (p < 0.05), operative vaginal deliveries and cesarean sections (p < 0.001), as well as the need for advanced neonatal resuscitation (p < 0.001). There was also a correlation between MSAF and low Apgar scores at five minutes (p < 0.001) and fetal-neonatal mortality (p < 0.001) but there was not a higher proportion of neonatal intensive care admissions (p > 0.05). We have observed a similar distribution of umbilical artery pH ranges in all groups (p > 0.05).MSAF was associated with an increase in the rate of pathological fetal heart rate patterns, intrapartum fevers, operative vaginal and cesarean section deliveries, need for neonatal resuscitation, low Apgar scores and higher fetal-neonatal mortality. Moreover, we found that the risks increase as the staining and consistency of the amniotic fluid evolves so it should alert the obstetrician and paediatrician to the potential adverse outcomes.

THE FREQUENCY OF FETAL BRADYCARDIA DURING SELECTIVE EPIDURAL ANAESTHESIA

The frequency of marked fetal bradycardia (FB) during selective lumbar epidural anaesthesia with 0.25% or 0.5% bupivacaine (Marcainr`, Bofors) without adrenaline in doses of 5 ml to 8 ml is reported. 35 patients were monitored by means of the Hewlett-Packard Cardiotocograph with Hon's spiral scalp electrode and a transcervical catheter connected to a Hewlett-Packard (1280 B/C) physiological pressure transducer. Only patients with a normal cardiotocogram (CTG) before anaesthesia are included. During the second stage pathological fetal heart rate (FHR) patterns and technical artefacts are common, therefore the CTGs recorded in this period were not considered. In the 35 patients the total time of intrauterine monitoring was 119 hours. During this period 125 doses of 0.25% and 23 doses of 0.5% bupivacaine were given. In 33 parturients the FHR changes observed were insignificant. In one case a period of marked FB was seen. One parturient developed acute hypotension with a synchronous FB while lying in the supi...