Average Fetal Heart Rate Research Articles

Efficacy of Intravenous Tenoxicam as an Analgesic during the First Stage of Labor : A Randomized Controlled Trial

Background: childbirth is one of the most painful events of a woman's life. The experience of labor pain is a complex, multidimensional response to sensory stimuli generated during parturition and its intensity can vary greatly. Unlike other acute and chronic pain experiences, labor pain is not associated with pathology, but with the most basic and fundamental of life’s experiences Aim of the work: this work aimed to study the efficacy of intravenous tenoxicam for labor analgesia. Patient and methods: this was two-arm, randomized controlled trial. The first arm (Group T) represented subjects who received tenoxicam. The second arm (Group R) represented subjects who received routine analgesic pethidine and it is given at a dose of 50 mg diluted over 10 ml of normal saline. The parturient woman was given 3-4 cm of diluted pethidine whenever she has intolerable pain. Results: this study included 260 subjects that were allocated into two arms: tenoxicam arm (n=118) and pethidine arm (n=142) as the control group. Tenoxicam group included 118 subjects and the pethidine group included 142 subjects. Maternal age was 23.74 ± 3.76 in tenoxicam group vs 23.99 ± 3.5 in pethidine group. Gestational age was 39.04 ± 1.42 in tenoxicam group vs 38.93 ± 1.5 in pethidine group. Birth weight was 3.43 ± 0.26 in tenoxicam arm vs 3.41 ± 0.26 in pethidine arm, average fetal heart rate was 140.1 ± 17.12 in tenoxicam arm vs 138.1 ± 16.39 pethidine arm, cervical dilatation was 4.19 ± 0.77 in tenoxicam arm vs 4.25 ± 0.7 and interval to delivery was 5.89 ± 1.29 in tenoxicam arm vs 6.2 ± 1.62 in pethidine arm. Conclusion: tenoxicam (40 mg iv), a long acting NSAID that induces analgesia by inhibiting peripheral prostaglandin synthesis, reduced postpartum uterine contraction pain without apparent maternal or neonatal adverse effects. Furthermore, tenoxicam exhibits superior analgesic properties over the routinely used pethidine as labor analgesic. Further studies should evaluate analgesic effects vs side effects of iv tenoxicam as a function of dosage or as part of combination therapy with different opioid analgesics.

ECG Electrode Configuration to Extract Real Time FECG Signals

Monitoring fetal health early in pregnancy helps to avert possible fetal damage and even fetal death. Among various fetal monitoring techniques the invasive fetal scalp electrode method is the most accurate method at labor. However this method may cause risk to the baby if used for antepartum monitoring. The Non-invasive fetal ECG (NIFECG) is a simple and the next best method to extract fetal heart rate (FHR) before full term. NIFECG can extract the fetal morphology from the FECG signal which can aid in diagnosing fetal health ahead of delivery. This paper aims to locate the most optimum points to place the ECG electrodes on the maternal abdomen so as to get the best FECG signals. After reviewing few previous techniques, we proposed three schemes using a standard 12 lead ECG recorder. It was observed that the scheme 2 successfully displayed the average FHR as compared to the ultrasound report of a single subject. A further researching and experimental procedures are required in this abdominal ECG (aECG) placement electrode positioning schemes before a standardized electrode configuration which can be introduced in clinical practice.

The variation of fetal heart rhythm towards delivery

In this paper, we investigate the variation of the fetal heart rate as we approach delivery. The fetal heart rate is affected by several factors, including the uterine contractions, the amount of oxygen in blood, the sex of the fetus, etc. We isolate specific biochemical markers or other measurable characteristics and compare plots expressing the average fetal heart rate versus the time remaining until the delivery, for subjects with different values in these characteristics. Our motivation is to study the effect of different values, related to a biochemical marker or characteristic, on the heart rate of the fetus. One important observation that came out from this study is the increased discriminating power presented between different groups of subjects, appearing in the time period before the delivery, where the heart works under unusual pressure. In some cases, even though the average fetal heart rate associated to each group can not be discriminated during the early stages, the differentiation becomes possible before delivery, since the group that is expected to react better under pressure achieves to keep the heart rate in higher levels.

Comparison of fetal and maternal heart rate measures using electrocardiographic and cardiotocographic methods

PurposeTo determine the reliability at term of: (1) two methods of measuring fetal heart rate (HR), electrocardiographic (ECG, the ‘gold standard’) and cardiotocographic (CTG) and (2) two ECG methods of measuring maternal HR variability over relatively brief periods of time (s–min). MethodsDuring 20min of rest (N=39) and during 2min of auditory stimulation (mother's recorded voice, n=19), fetal HR data were collected using an ECG (Monica AN24) and a Hewlett-Packard Model 1351A CTG. Simultaneously, maternal HR data (n=37) were collected using the same ECG device (Monica AN24) and a second stand-alone cardiac monitor (Spacelab 514T cardiac monitor with a QRS detector). ResultsDuring 20min of maternal rest, correlations of individual fetal CTG with ECG measures of HR at each second were moderate to high (r=.57–.97) for 77% of fetuses. Correlations of HR averaged over fetuses and over each of the 20min were high (r=.93–.97); fetal HR averaged over 20min varied between devices from 0.0 to 0.8bpm. During 2min of maternal voice presentation, correlations of fetal HR over each second were moderate to high (r=.54–.99) for 95% of fetuses and high (all rs=.99) when averaged across fetuses in 30s or 2min epochs. Average fetal HR between devices over the 2min voice varied from 0.0 to 0.6bpm. Correlations and/or % agreement between the two ECG methods of measuring maternal HR were high. Average maternal HR over 10min showed 81% of pairs with a difference of ≤1bpm; correlations for HR variability measures varied from r=.89 to .97. ConclusionsGood reliability was demonstrated between individual spontaneous and auditory induced fetal CTG and ECG with high correlations when HR data were averaged over fetuses or in 30–120s epochs. High reliability of maternal HR measures was obtained using two ECG devices.

Influence of exercise in pregnancy on fetal heart response during labor and delivery (886.5)

Current research supports the health benefits of exercise during pregnancy for mother and baby. However, scant research has focused on how maternal exercise during pregnancy influences fetal heart response during labor and delivery. The purpose of this study was to compare the effects of exercise throughout pregnancy on fetal heart response to the stress of labor and delivery. We hypothesized that during labor and delivery there would be lower baseline fetal heart rate (HR), increased fetal heart rate variability (HRV), and no differences in fetal accelerations and decelerations in fetuses exposed to maternal exercise relative to controls. The Modifiable Physical Activity questionnaire was used to classify controls and exercisers. Based on routine fetal HR recordings, we measured fetal baseline HR, HRV, accelerations, and decelerations and birth measures. Group differences were tested using t‐tests. There were no differences found between the mother’s age, gestational age, gravida and parity. No statistical difference was found in average fetal HR and HRV; however, there is a trend towards increased variability among the exercise group. These data suggest babies exposed to maternal exercise respond the same, or better, during the physiologic stress of labor and delivery. These findings are applicable in regards to the potential to improve pregnancy outcomes in the US.

Effects of maternal breathing rate, psychiatric status, and cortisol on fetal heart rate

Women's experiences during pregnancy are predictive of variation in neurobehavioral profiles in their children. Few studies have assessed these relationships during the prenatal period. In 113 women in the 36(th) -38(th) gestational week (mean age 26.3 ± 5.4 years), electrocardiogram, blood pressure, respiration, salivary cortisol, and fetal heart rate (HR) were measured during baseline, a psychological challenge (Stroop color-word matching task), and a standardized paced breathing protocol. Subjects underwent the Structured Clinical Interview for DSM-IV prior to testing and were grouped as: depressed, co-morbid for depression and anxiety, anxiety disorder only, and control. There was a significant main effect of maternal diagnostic group on fetal HR only during the Stroop task: fetuses of women in the co-morbid group had a greater HR increase compared to controls (p < .05). Overall, fetuses showed robust increases in HR during paced breathing (p < .0001), and there was no significant difference by maternal diagnosis. For both tasks, changes in fetal HR were independent of women's concurrent cardiorespiratory activity. Finally, although cortisol was higher in the co-morbid group (p < .05), across all participants, there was a trend for maternal baseline cortisol to be positively associated with average fetal HR (p = .06). These findings indicate that variation in fetal HR reactivity-an index of emerging regulatory capacities-is likely influenced by multiple acute and chronic factors associated with women's psychobiology.

Fetal Circulatory Responses to Maternal Blood Loss

We examined the fetal circulatory responses to maternal blood loss in pregnant women during the third trimester. Seven healthy women with placenta previa and singleton pregnancies underwent phlebotomies in an autologous donation program. Four hundred milliliters of blood was collected within 15 min at 34 and 35 weeks of gestation. Continuous electric recordings of fetal heart rate were performed during the first blood collection, and the maternal uterine artery (UtA), umbilical artery (UmA) and fetal middle cerebral artery (MCA) Doppler velocity waveforms were recorded before, immediately after and 24 h after the second collection in each patient. The average fetal heart rate, maternal UtA and UmA pulsatility indices did not change measurably during or after maternal blood collections. However, the average fetal MCA pulsatility index decreased significantly 24 h after maternal blood loss. The observation of a decrease in fetal MCA pulsatility index may indicate delayed fetal asphyxia following mild maternal hemorrhage.

Effects of Impulse Noise Stimulation on Electrocorticogram and Heart Rate

It is now recognized that high-level impulse noises penetrate the uterus of pregnant sheep, elevate thresholds of fetal auditory-evoked potential and produce damage to fetal inner ear hair cells. However, little is known about functional effects of airborne impulse noise on the late-term fetus. In the present study, the effects of a series of 20 impulses on the behavioral state of 6 fetal sheep were tested. Noise impulses produced 169.3 peak sound pressure level (pSPL) in air. Peak levels recorded near the fetal head averaged 161.1 dB. Impulses delivered to the fetus during periods of NREM sleep resulted in a decrease in average fetal heart rate (FHR) from 185 ± 22 beats/min (bpm) before stimulation to 174 ± 23 bpm 2–5 s after stimulation (p < 0.05). During REM sleep, an FHR acceleration occurred (before stimulation: 177 ± 24 bpm, after stimulation: 189 ± 31 bpm; p < 0.05). Impulse exposure during NREM sleep resulted in reductions in delta-, theta- and alpha-band powers. As a consequence, total power decreased from 100 to 72 ± 16% (p < 0.05). During REM sleep, stimulation provoked a short decrease in total band power from 100 to 73 ± 20% and a similar decrease in the theta- and beta-band powers. The results indicated that impulse noise evoked short-term alterations in FHR and cortical activity. These changes were mediated by auditory brain stem activation that led to cortical desynchronization during both NREM and REM sleep in late-term fetal sheep.

Maturation of fetal heart rate and body movement in 24–33‐week‐old fetuses threatening to deliver prematurely

Maturation of spontaneous cardiac and body movement behavior from 24 to 33 weeks gestational age was characterized prospectively in 168 high-risk fetuses threatening to deliver prematurely. Forty-eight, low-risk fetuses delivering as healthy full-term infants served as a comparison group. Fetuses were classified on the basis of gestational age at time of testing and newborn outcome following delivery (high-risk: premature compromised, premature healthy, term healthy infant; low-risk term healthy). In the high-risk group, the average fetal heart rate was greater and decreased over gestation from 148 to 140 bpm, regardless of outcome. In the low-risk group, it decreased from 145 to 138 bpm. In high- and low-risk groups, the average number of heart rate accelerations ≥ 15 bpm increased over gestation from 2–3 to 8 while the average number of maternally perceived movements decreased. It was concluded that maturational changes in spontaneous fetal heart rate and maternally perceived body movements in fetuses threatening to deliver prematurely parallel those of low-risk fetuses. © 2001 John Wiley & Sons, Inc. Dev Psychobiol 38: 78–86, 2001

Maturation of fetal heart rate and body movement in 24-33-week-old fetuses threatening to deliver prematurely

Maturation of spontaneous cardiac and body movement behavior from 24 to 33 weeks gestational age was characterized prospectively in 168 high-risk fetuses threatening to deliver prematurely. Forty-eight, low-risk fetuses delivering as healthy full-term infants served as a comparison group. Fetuses were classified on the basis of gestational age at time of testing and newborn outcome following delivery (high-risk: premature compromised, premature healthy, term healthy infant; low-risk term healthy). In the high-risk group, the average fetal heart rate was greater and decreased over gestation from 148 to 140 bpm, regardless of outcome. In the low-risk group, it decreased from 145 to 138 bpm. In high- and low-risk groups, the average number of heart rate accelerations greater than or = 15 bpm increased over gestation from 2-3 to 8 while the average number of maternally perceived movements decreased. It was concluded that maturational changes in spontaneous fetal heart rate and maternally perceived body movements in fetuses threatening to deliver prematurely parallel those of low-risk fetuses.

Human Fetal Heart Rate Dishabituation between Thirty and Thirty-Two Weeks Gestation

Few studies of human fetal habituation have included dishabituation procedures (i.e., assessment of the reemergence of a habituated response) to determine if response decrements are the result of reevaluation of information (a brain process) or fatigue of peripheral receptors. The purpose of this study is to describe the ability of the human fetus to learn and recall information with procedures to assess the central nervous system. Fetal heart rate (FHR) of 84 fetuses between 30 and 32 weeks gestational age was examined in response to 3 series of vibroacoustic (VA) stimuli presented at pseudorandom intervals of 25-45 s over the head of the fetus. Responses to the first series of 15 stimuli (S1) were compared with an identical second series of 15 stimuli (S1) presented over the head of the fetus. Between the 2 series, a novel (dishabituating) VA stimulus (S2) was presented, differing from S1 in intensity and frequency. The third series of S1s was applied to the mother's thigh as a control for possible maternal responses to the stimulus. Prestimulus FHR was computed during a 5 s interval before each stimulus, and mean FHR was computed during the intertrial interval (average FHR). The response to S1 during the first series of trials (1-15) produced a sustained rise in both prestimulus and average FHR, r(83) = .90, p < .001. After the novel S2 (trial 16) the rate of change was attenuated for average FHR, r(83) = .12, ns, to S1 for trials 17-31 but not prestimulus FHR, r(83) = .50, p < .001. The decrease in FHR response was reestablished when stimulation was applied to mother's thigh, trials 32-41, r(83) = .92, p < .001. A significant habituation pattern across trials was observed for the first series of S1s when prestimulus HR was subtracted from each preceding average FHR value (delta FHR). After the single novel stimulus (S2), the FHR response to S1 reemerged. All combinations of beginning and ending series slopes were compared, and only the rate of change during the last 4 trials of the initial presentation of S1 and the first 4 trials after the novel stimulus was significant, F(1, 82) = 9.21, p < .003. Uterine contractions collected from the continuous record were not related to the presentation of the novel stimulus, chi 2(1, N = 84) = 0.59, p < .50, ns, or delta FHR slope after the novel stimulus, chi 2(9, N = 84) = 10.52, p < .50, ns. These results established that the 32 week human fetus is capable of detecting, habituating, and dishabituating to an external stimulus and support the premise that areas of the human fetal central nervous system critical for detecting and discriminating information and for learning and memory have developed by the early third trimester.

The relationship between heart rate and eye movement in the human fetus at 38–40 weeks of gestation

The purpose of this study was to compare two different methods for assessing fetal heart rate (FHR) - fetal eye movement (FEM) synchronization: (1) periods of high (HV) and low (LV) variability in the FHR and the presence (EM) and absence (NEM) of FEM were determined by visual inspection and the degree of association between FHR and FEM was assessed in terms of the fraction of study time for which no periods of LV-NEM and HV-EM could be identified; and (2) the maximum cross-correlation coefficient ( r max) and the lag at r max ( L max) were determined by direct computer analysis of FHR and FEM data for each fetus. Twenty normal human fetuses between 38 and 40 weeks of gestation were examined for a total of 2051 min (mean 103 min, range 72–150 min). In general, the state HV-EM was observed approximately twice as often as was the state LV-NEM; neither of these two states could be identified during 12.4% of the study time. The coefficient r max was calculated assuming a sliding 3-min moving window, using either the average FHR (mean 0.53, range 0.31–0.85) or the variability in the FHR (mean 0.52, range 0.18–0.77). No relationship was found between r max and L max calculated using the mean FHR and the fraction of time for which no state could be identified ( P = 0.995). When the cross-correlation analysis was performed using FHR variability, a statistically significant relationship was found between the periods of no coincidence (of states LV-NEM and HV-EM) and r max and L max ( r 2 = 0.32; P = 0.04). However, the low value of r 2 implied that 68% of the variability in the subjective measure is due to factors other than r max and L max. Although this discrepancy may be the result of an inappropriate selection of objective measures, the low correlation probably reflects the subjective nature of visually assessing FHR-FEM organization.

Fetal Heart Rate Response to Maternal Exertion

Doppler monitoring of fetal heart rates during maternal exertion has suggested that fetal bradycardia occurs frequently during vigorous exercise, causing concern for fetal safety. Doppler determination of fetal heart rate during vigorous maternal effort is difficult. To avoid motion artifact, we observed fetal heart rate using two-dimensional ultrasound and determined the incidence of fetal bradycardia in 45 pregnant women (age, 29.0 +/- 3.7 years [mean +/- SD]; gestational age, 25.2 +/- 3.0 weeks) during 85 submaximal and 79 maximal cycle ergometer tests. Average fetal heart rate did not change during exercise. A single episode of fetal bradycardia (heart rate less than 110 beats per minute for greater than or equal to 10 s) occurred during submaximal exertion during a maternal vasovagal episode. Sixteen episodes of fetal bradycardia were noted within three minutes after cessation of exercise, 15 of which followed maximal maternal effort. We conclude that brief submaximal maternal exercise up to approximately 70% of maximal aerobic power (maternal heart rate less than or equal to 148 beats per minute) does not affect fetal heart rate. In contrast to submaximal maternal exertion, maximal exertion is commonly followed by fetal bradycardia. This may indicate inadequate fetal gas exchange.

Fetal Heart Rate Response to Maternal Exertion

Doppler monitoring of fetal heart rates during maternal exertion has suggested that fetal bradycardia occurs frequently during vigorous exercise, causing concern for fetal safety. Doppler determination of fetal heart rate during vigorous maternal effort is difficult. To avoid motion artifact, we observed fetal heart rate using two-dimensional ultrasound and determined the incidence of fetal bradycardia in 45 pregnant women (age, 29.0 +/- 3.7 years [mean +/- SD]; gestational age, 25.2 +/- 3.0 weeks) during 85 submaximal and 79 maximal cycle ergometer tests. Average fetal heart rate did not change during exercise. A single episode of fetal bradycardia (heart rate less than 110 beats per minute for greater than or equal to 10 s) occurred during submaximal exertion during a maternal vasovagal episode. Sixteen episodes of fetal bradycardia were noted within three minutes after cessation of exercise, 15 of which followed maximal maternal effort. We conclude that brief submaximal maternal exercise up to approximately 70% of maximal aerobic power (maternal heart rate less than or equal to 148 beats per minute) does not affect fetal heart rate. In contrast to submaximal maternal exertion, maximal exertion is commonly followed by fetal bradycardia. This may indicate inadequate fetal gas exchange.

Fetal heart rate pattern before and after paracervical anesthesia. A prospective study.

A prospective study of the fetal heart rate pattern during labor before and after paracervical blockade (PCB) was performed. The material comprised 469 women in labor, or 28% of 1673 women delivered during a 6-month period. The majority of the anesthesias (87%) were administered by specially trained midwives. Bupivacain (Marcain) was the anesthetic used. The injections were made at four different points at a cervical diameter of 3-9 cm. The concentration of the anesthetic was 0.25 or 1.25% generally in 10 ml of normal saline. A second PCB was administered in 54 patients at least one hour after the preceding one. Fetal heart rate (FHR) was recorded via a scalp electrode and the pattern studied 15 min before and 30 min after the injection of the anesthetic. Bradycardia was defined as a persistent deceleration exceeding 3 min and occurring within 30 min of the PCB. Variability and acceleration pattern persisted independently of the PCB. Following PCB, decelerations of all types increased, while the basal rhythm decreased by on average 1.5 beats/min. Following PCB fetal bradycardia occurred in 1.9%. The bradycardia persisted on average for 6.5 min with a lowest average FHR of 73 beats/min. Retrospectively, 6 out of 9 infants exhibited recognized risk factors for bradycardia. All infants with bradycardia scored 9-10/5 min, according to the Apgar rating scale and all had a normal development with regard to growth, motor and speech development at the age of 2 years. There were no significant differences in vaginal operative deliveries between the PCB and the non-PCB group.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of acute hypoxemia and respiratory acidosis on the fetal heart rate in monkeys

The fetal heart rate (FHR) response to acute nonacidemic hypoxemia and to acute respiratory acidosis was studied in unanesthetized pregnant monkeys by means of chronically implanted catheters and electrodes. Average FHR and short- and long-term FHR variability were analyzed separately. The FHR response to either hypoxemia or hypercapnia consisted of slowing and increased variability. The slowing was more consistent with hypercapnia than with hypoxemia. Long-term FHR variability increased with both test stresses. The increase in short-term FHR variability was much greater in response to hypoxemia than to hypercapnia. Both the FHR slowing and the increases in variability in response to the test stresses were reduced by prior administration of atropine to the fetus.

The effect of cigaret smoking during pregnancy upon the fetal heart rate

A study of fetal heart rate before and after maternal smoking has been made a total of 81 times on 5 patients. The object of the study has been to determine the effect, if any, of maternal smoking on fetal heart rate. It was felt that if fetal heart rate was altered by maternal smoking, this change would indicate that the toxic products of tobacco smoke do pass through the human placenta and enter the fetal circulation. The results of the observations are as follows: 1.1. The average fetal heart rate for five minutes before smoking was 144.0 ± 0.14. The average fetal heart rate for the eighth to the twelfth minute after a cigaret was lighted and smoking begun, was 149.0 ± 0.13. The average increase in the rate was 5.0 ± 0.19 beats. Since the difference in rates before and after smoking is more than 25 times the probable error of the difference, the effect of smoking is actual.2.2. Of the 5 patients, 4 showed an increase in fetal heart rate after smoking, while the fifth showed a decrease. The 4 showing increases were habitual smokers who inhaled the smoke. The patient showing decrease had never smoked before, did not inhale, and expelled the smoke from her mouth as quickly as possible.3.3. There were occasional negative trials in each of the 4 patients showing increase. These occurred for the most part at times when the fetal heart rate during the control period was above its average.