Precipitated opiate abstinence in utero

Following direct infusion of morphine (0.6 to 80.0 mg/hr) to the fetal lamb for 2 to 6 hours, naloxone administration precipitated a fetal abstinence syndrome consisting of desynchronization of electrocortical activity; increased total body movements, neck tone, and eye movements; continuous rapid, deep breathing movements; immediate bradycardia associated with transient increases in systolic, diastolic, and pulse pressures; and meconium staining of the amniotic fluid. This syndrome resembles that observed in the opiate-abstinent human neonate.     

The relationship between fetal activity and behavioral states and fetal breathing movements in normal and growth-retarded fetuses

The incidence of fetal breathing was studied during the course of behavioral state observations on 28 low-risk fetuses between 32 and 40 weeks' gestational age and on 12 growth-retarded fetuses between 36 and 40 weeks. Real-time ultrasound scanners were used to detect fetal eye, body, and breathing movements, and the fetal heart rate was recorded continuously. The mean duration of the observation sessions was 110 minutes. The mean incidence of fetal breathing was greater during periods of fetal activity (body and eye movements present, greater heart rate variability) than during quiescence (body and eye movements absent, narrowed heart rate variability) at all gestational ages studied in both low-risk and growth-retarded fetuses. During periods when one of the state variables (body movements, eye movements, heart rate pattern) was in its active condition while the other two were quiet, or the reverse, the incidence of fetal breathing was intermediate between those found when all three state variables were in agreement. After behavioral states had developed, at 38 and 40 weeks, the mean incidence of fetal breathing in the low-risk fetuses was greater during active states than during the quiet state. There was no apparent increase in the degree of linkage between fetal breathing and other expressions of fetal activity after the emergence of behavioral states.     

Influence of the fetal scalp electrode stimulation test on fetal heart rate and body movements in quiet and active behavioral states during labor

Thirty women were studied to examine the effect of fetal scalp stimulation on fetal heart rate (FHR) accelerations and gross body movements in quiet and active fetal behavioral states during the active phase of labor. Stimulation was performed by five consecutive tractions of the fetal scalp electrode. Fetal response in terms of fetal movements and FHR accelerations occurring within 15 seconds after stimulation was observed in all fetuses of the active state group. In the quiet state group 14 of 15 fetuses responded with body movements and in 12 fetuses FHR accelerations were observed. Subsequently, most of the fetuses returned to the quiet state. We suggest that a normal and healthy fetus is expected to respond to the fetal scalp electrode stimulation test even in the quiet behavioral state.     

Behavior-state–dependent changes in human fetal pulmonary blood flow velocity waveforms

Objective: To establish the influence of fetal behavior states on venous and arterial pulmonary blood flow velocity waveforms in the normally developing term fetus.Methods: The relation between venous and arterial pulmonary blood flow velocity waveforms and fetal behavior states was investigated in 18 normal term fetuses. Recordings of the venous pulmonary blood flow velocity waveforms were obtained just proximal to the entrance in the left atrium, and the arterial pulmonary blood flow velocity waveforms were taken from the most proximal branch of the pulmonary artery in the same lung using color Doppler imaging. Time-averaged peak systolic, peak diastolic, and end-diastolic flow velocity; peak systolic to peak diastolic ratio; pulsatility index; and fetal heart rate were calculated from both venous and arterial Doppler recordings obtained during behavior states 1F (quiet sleep) and 2F (active sleep). Fetal behavior states were determined from combined recordings of fetal eye and body movements.Results: Recordings of sufficient quality for analysis were obtained from ten fetuses. Venous pulmonary blood flow velocity waveforms demonstrated a statistically significant increase in time-averaged peak diastolic and end-diastolic velocity during fetal behavior state 2F. No behavior-state-related changes were observed for the arterial pulmonary blood flow velocity waveform.Conclusion: The data suggest an increased pressure gradient between the pulmonary venous system and the left atrium during behavior state 2F. Flow velocity waveforms from the proximal arterial pulmonary branch are independent of behavioral state.     

Intrapartum fetal vibratory acoustic stimulation during spontaneous and induced states of low activity and low heart rate variability

Fetal response to vibratory acoustic stimulation (VAS) was studied in 12 healthy parturients in the active phase of labor. All fetuses were evaluated in both spontaneous and analgesia-induced states of low activity and low cardiac beat-to-beat variability. Analgesia was induced with intravenous maternal administration of meperidine, 0.8 mg/kg, plus a fixed dose of promethazine (25 mg). The vibratory acoustic stimulus was applied ten minutes after the start of a fetal quiet state, and ten minutes of fetal behavior was observed after application of the stimulus. The number and mean duration of fetal body movements in the unmedicated fetuses were statistically significantly higher than in the medicated group. Similarly, the number of fetal heart rate accelerations was significantly higher in the unmedicated fetuses than in the medicated ones. Ten minutes after VAS no fetus in the unmedicated group was in a quiet behavioral state, while 10 of 12 medicated fetuses (83%) returned to a quiet state.     

The ultrasonic Doppler fetal actocardiogram and its computer processing

Gross fetal movement was detected using a lower frequency ultrasonic Doppler shift than that used in the study of fetal heart action. The movement signal was changed into deflection which was recorded on CTG chart simultaneously with the fetal heart rate (FHR), and was called the fetal actocardiogram. Visual analysis of the actocardiogram showed bursts of active fetal movements in the active fetal state which were concordant with acceleration of FHR. The analysis was useful in the study of fetal behavioural states. Imminent fetal distress produced a loss of FHR acceleration which was accompanied by a burst of fetal movement, i.e. a true non-reactive state of the FHR. The output of the actocardiograph was analysed using a PC98XA computer with a simple statistics of deflection amplitude and interval, displayed as 3-dimensional histograms of the number and frequency, and the formation of the envelope curve of the deflections. The study demonstrated that it is possible to recognize fetal behavioural states automatically. This includes active and resting fetal states as well as fetal breathing movements.     

Influence of meperidine on fetal movements and heart rate beat-to-beat variability in the active phase of labor

Eleven parturients were studied in the active phase of labor. Fetal movements, fetal heart rate, and short-term beat-to-beat variability as well as uterine contractions were evaluated for two 40-minute recording periods before and after maternal intravenous administration of 50 mg meperidine. Meperidine depressed fetal activity and increased the duration and frequency of uterine contractions. Fetal movements were significantly reduced from 156 to 60 and their relative duration from 8.6 +/- 6.0% to 2.4 +/- 2.6% (p less than 0.01). The short-term fetal heart rate beat-to-beat variability was reduced at the baseline period 5.22 +/- 1.02 versus 4.62 +/- 1.47 (p less than 0.05) but not during uterine contractions or fetal movements. The frequency of uterine contractions increased from 3.1 +/- 0.8 to 3.7 +/- 0.7 per 10 minutes (p less than 0.01), and their relative duration from 35.3 +/- 6.9% to 40.1 +/- 5.9% (p less than 0.05).     

Intrauterine fetal activity in at term and prolonged pregnancies

Fetal body movements and breathing movements were recorded with a real time ultrasound scanner in 26 fetuses. There were two recording periods of 25 min each, before and half and hour after maternal IV administration of 50 gr glucose. Six fetuses were at 280 days of gestation (Group A), twelve fetuses were at 294 days of gestation (group B), eight fetuses at 294 days gestation were classified as stage I postmature (group C). The incidence of fetal body movements was not significantly different in the three groups. Maternal glucose administration had no significant influence on fetal body movements in any group. On the other hand fetal breathing activity was significantly increased in all three groups after maternal glucose administration. Breathing activity was significantly greater in group A when compared to group C in both recording periods, and when compared to group B in the period which followed maternal glucose administration. It is concluded that fetal breathing activity is reduced in prolonged pregnancies.     

Braxton Hicks' contractions and motor behavior in the near-term human fetus

The transient relationship between Braxton Hicks' contractions and fetal motor behavior was studied in 14 healthy nulliparous women near term. Two-hour recordings of fetal heart rate and uterine contractions and of real-time scanning for fetal body movements, breathing, and eye movements were made. The recordings were divided into state 1F and non-state 1F. Braxton Hicks' contractions were not influenced by fetal behavioral states and state changes were not related to these contractions. Fetal body movements did not stimulate contractions, but contractions coincided with a specific clustering of body movements during the ascending part of contractions. Breathing was clustered during the descending part of short-lasting contractions but decreased gradually during the long-lasting ones. Heart rate variation was increased during contractions.     

Fetal ethology and its relevance to perinatal medicine

Fetal ethology means fetal activity and behavioral states in the uterine environment. Behavioral states may be defined by various measurable physiological variables, such as heart and respiratory rates, eye movements, body tone and body movements. Fetal motor behavior provides information about the early stages of the neurodevelopmental process. Movement was the first aspect of fetal behavior, the clinical significance of which became was recognized. Fetal behavior provides an opportunity for studying motor, sensory and cognitive functions in the fetus. Behavior can be utilized to study the immediate well-being of the fetus. The latter can be compromised as a result of a number of pathological factors. In high risk pregnancies, the study of fetal behavior may help the clinician to establish the optimum time for the delivery.     

Effect of maternal intravenous glucose administration on fetal heart rate patterns and fetal breathing

This study was undertaken to evaluate the effect of maternal intravenous (IV) administration of glucose on fetal breathing and its associated fetal heart patterns. Sixteen healthy women at term gestation participated in the study. The outcome of each of the pregnancies was normal. Fetal breathing and fetal electrocardiograms were simultaneously recorded by real time sonography and a fetal monitor respectively, and then digitized into a microcomputer. These women were studied for a 25-minute control period, given 50 gm of glucose IV and then, 20 minutes later, restudied for an additional 25-minute period. The results indicate that fetal breathing movements lasted for 24.8 +/- 6.2 percent of the time during the control period (mean +/- SEM) and were increased to 63.2 +/- 11.5 percent following the injection of glucose (P less than 0.01). Fetal heart rate decreased during fetal breathing by 2.3 and 2.1 beats per minute, before and after glucose administration, respectively (NS). Fetal breathing was associated with increased beat-to-beat variability by 1.32 +/- 0.5 and 1.27 +/- 0.3, before and after glucose administration, respectively (NS). This study confirms previous reports that the amount of time the fetus spends making breathing movements is significantly increased following maternal glucose administration, and demonstrates that the injection of glucose does not alter the modulation of fetal heart rate and beat-to-beat variability by fetal breathing.     

The development of fetal behavioural states: a longitudinal study

In order to evaluate the development of fetal behavioural states a longitudinal study was performed on 35 healthy fetuses during the last trimester of pregnancy. Fetal heart rate (FHR), gross fetal body movements (FM), fetal eye movements (FEM), fetal breathing movements (FBM) and micturition were simultaneously studied at two-week intervals from 28 weeks gestation onwards. Well-defined fetal behavioural states were observed only after 36 weeks gestation. Between 28 and 36 weeks the quiet-activity cycle of FHR was always detected and some fetal biophysical activities seemed to become related around this cycle.     

The fetal behavioural states: an ultrasonic study

In order to accurately detect the fetal behavioural state, we simultaneously measured fetal heart rate and multiple fetal activities in 27 healthy pregnant women at 38 to 40 weeks of gestation. We ultrasonically identified gross body movements, breathing movements and micturition. Analysis of fetal heart rate allowed us to distinguish two different patterns of fetal behaviour: active and quiet phases. The frequency distribution of the analysed fetal events was significantly different in these two phases. These data suggest that a complete biophysical profile of the fetus is effective in differentiating behavioural states and may improve the predictive accuracy of fetal heart rate analysis alone.     

The effect of magnesium sulfate on the behavioral activities of fetal goats

OBJECTIVES: To investigate fetal heart rate accelerations, fetal breathing movements, and fetal electrocortical activities during administration of magnesium sulfate to fetal goats. METHODS: The fetal heart rate accelerations, fetal breathing movements, and fetal electrocortical activities during 6 hours of continuous magnesium sulfate infusion into the fetal jugular vein were examined in 8 chronically instrumented fetal goats at 124-131 days of gestation. Fetal breathing movements were defined as repetitive negative fluctuations of the fetal tracheal pressure. Fetal electrocortical activities were assessed by visual analysis of periods of high-voltage and low-voltage electrocortical activities. RESULTS: Continuous infusion of magnesium sulfate for 6 hours significantly increased the fetal plasma magnesium concentration from 2.8 +/- 1.2 to 8.3 +/- 2.6 mg/dL without significant changes in fetal arterial blood gases. The incidence of fetal heart rate accelerations during magnesium infusion was significantly decreased from that found during the control periods. After 2 hours of infusion, the incidence of fetal breathing movements significantly decreased from 33.9% +/- 20.5% to 1.2% +/- 1.4% and remained at this level during the remaining 4 hours of magnesium infusion. The percentage of time that the fetuses were found to have low-voltage electrocortical activities decreased from 51.6% +/- 9.0% to 40.4% +/- 8.2% after 2 hours of infusion but recovered to 49.9% +/- 12.0% by 6 hours of magnesium infusion. CONCLUSION: We concluded that fetal magnesium sulfate administration affected fetal heart rate accelerations and fetal breathing movements continuously but electrocortical activities only temporarily during 6 hours of observations.     

Behavioural states: concomitants, clinical implications and the assessment of the condition of the nervous system

Behavioural states do exist in the human fetus. These states have been called 1F to 4F and resemble states 1 to 4 in the neonate. States 1F and 2F are similar to 'non-REM sleep' or 'quiet sleep' and 'REM-sleep' or 'active sleep', respectively. The fetus spends most of the time in these two states. Each state can be characterized by a particular combination of 3 variables: presence or absence of fetal eye movements and body movements, and fetal heart rate patterns A, B, C and D. From about 36 wk these combinations can be recognized during longer periods without interruptions, and with clear state-transitions. At 32 wk a certain linkage between the three variables is already present but a step-wise increase can be seen between 36 and 38 wk. Fetal breathing, mouthing movements and fetal voiding are state concomitants. Breathing movements are much more regular during state 1F than during state 2F, while the incidence is increased in 2F. It is demonstrated that knowledge of fetal behavioural states is necessary for an adequate interpretation of the fetal heart rate patterns. The concept of behavioural states may be useful for the early detection of disturbances of the developing fetal nervous system. It is therefore concluded that further studies on fetal behaviour have to be 'standardized' for behavioural states.     

Evaluation of fetal development and well-being with ultrasonic Doppler fetal actocardiogram

A new ultrasonic technique for objective, continuous and simple recordings method of fetal movements on CTG chart has been introduced. Fetal activity and heart-rate will be correlated. This allows a differentiation of fetal active and resting states. The duration of the first one was 24 to 150 minutes, that of the last one 10 to 36 minutes. Fetal actogram is useful in the prediction of imminent fetal distress.     

A randomised controlled comparison of betamethasone with dexamethasone: effects on the antenatal fetal heart rate

Objective To compare the effects of maternal administration of betamethasone and dexamethasone on fetal heart rate, using computerised numerical analyses, and to examine the association between changes in short term variation and the timing and indication for delivery.
Setting John Radcliffe Hospital, Oxford.
Sample Fifty-nine women with singleton pregnancies, who were at risk of delivery before 34 weeks of gestation, had received no steroids in the preceding week and could give informed consent.
Methods Women were randomised on a double-blind basis to receive either betamethasone or dexamethasone. The fetal heart rate was recorded (60-minute duration at similar times of day) before steroid administration and on each of the following two days; changes were measured by computerised analyses.
Main outcome measures Changes in short term variation and long term variation of fetal heart rate or the number of fetal movements. Statistical analysis was nonparametric.
Results Betamethasone and dexamethasone had no differential effects on the computerised cardiotocography. However, both steroids decreased baseline fetal heart rate, increased long term variation, increased short term variation, and decreased fetal movements on the first day after steroid administration, and decreased high fetal heart rate variation and decelerations on the second day. Among 13 women who were delivered within one week of steroid administration, smaller rises in short term variation on day one were associated with delivery for fetal indications.
Conclusions Both betamethasone and dexamethasone produced transient, unexplained changes in the fetal heart rate over the two days following steroid administration. Larger changes in short term variation were associated with fetal wellbeing. It is important to recognise that such changes are a physiological response of the human fetus to steroid administration.     

Behavioral states and the peripartum period.

Fetal movements with their associated FHR accelerations, as well as the cyclic alternation between episodes of low and high FHR variability, particularly in late pregnancy, give a clear indication of the fetal rest-activity cycle. FHR variability changes during labor indicate that the rest-activity cycle continues even though perceived movements may diminish and fetal breathing may stop. Fetal behavioral states, known to be present by term and characterized by the concordant association of fetal movements, continue during labor. However, not all labors show evidence of fetal behavior despite a normal outcome, and the significance of this remains unknown. The influence of the fetal rest-activity cycle on FHR variability is such that recognition of behavioral cycles, when present, is essential for appropriate interpretation of the FHR during labor.     

Effect of intravenous glucose injection on human maternal and fetal heart rate at term

The effects of maternal intravenous glucose administration (25 gm) on maternal heart rate, fetal heart rate, gross fetal body movements, and fetal heart rate accelerations was measured in 11 healthy pregnant women at 38 to 40 weeks' gestational age. Mean maternal heart rate increased from 78.3 ± 0.8 bpm during the control period to 82.7 ± 0.5 bpm at 30 to 85 minutes following glucose injections (p < 0.01). Mean fetal heart rate rose from 137.8 ± 0.4 bpm to 142.4 ± 0.3 bpm at 50 to 95 minutes following injections (p < 0.001). The incidence of gross fetal body movements and the number, duration, and amplitude of fetal heart rate accelerations did not change following glucose injection. We conclude that maternal glucose administration near term results in a small but significant increase in the mean maternal heart rate and fetal heart rate and no change in the incidence of gross fetal body movements or in fetal heart rate accelerations.     

Computer processing of the ultrasonic Doppler actographic fetal movement signals

Computer analysis of ultrasonic Doppler actographic signals was done in the fetal active state, resting state and during fetal breathing movement (FBM) in order to more objectively study fetal movements. 1) The amplitude and interval of movement signal spikes were analyzed in 11 voltage steps between 0.05 and 0.55V. The interval distribution showed a uniform pattern in all states when the signals were analyzed at levels below 0.10V. 2) In the fetal resting state, almost all spikes were distributed in the lowest level of amplitude. 3) In the fetal active state, the mean values for spike amplitude were high and the coefficients of variation (CV) were large. The 3-dimensional interval number histograms showed wide distribution until high amplitude and long interval steps. 4) In FBM, the mean values for spike amplitude and CV were smaller, respectively, than those in the active state and the spikes distributed in the short interval steps of 0.5-2.0 seconds. 5) The envelope processing was useful for easier recognition of fetal movement burst in the fetal active state. A very low envelope was formed in the resting state. Analyses during FBM revealed a flat but elevated envelope. The results show the possibility of automatic and objective recognition of fetal behavioral states.