Synchronous cardiotocographic registration of fetal body and respiratory movements in placenta insufficiency

The extent of fetal movements and their reflections in the cardiogramme were studied in 44 normotrophic and 39 hypotrophic fetuses under standardized conditions using real time ultrasound examination of fetal body and respiratory movements and synchronous registration of fetal cardiogrammes from a uterus without labour. Altogether, hypotrophic fetuses exhibited fewer movements than normotrophic fetuses did. Numbers and parameters of accelerations in fetal heart rate occurring in connection with fetal body movements were less marked, too. The acceleration amplitude was particularly significant. Further comparisons between fetuses born with pHa greater than or equal to 7.20 and less than 7.20 or 1- and 5-minute Apgar scores greater than or equal to 8 points and less than or equal to 7 points revealed statistically significant (alpha = 0.05) differences in the frequency of movements and movement-associated accelerations in fetal heart rate only in fetuses with a body weight less than or equal to the 5th weight percentile according to Kyank (n = 21). Fetuses with a body weight between the 6th and the 10th weight percentiles (n = 18) and normotrophic fetuses did not, or did only faintly, reveal these differences. A ratio calculated from the acceleration amplitudes and the durations of associated body movements differed significantly between impaired and unimpaired born fetuses during defined intervals of the duration of fetal body movements.     

The relationship between movements and accelerations in fetal heart rate at twenty-four to thirty-two weeks' gestation

The purpose of this study was to establish the relationship between fetal heart rate accelerations and fetal body movements in fetuses at 24 to 32 weeks' gestation. The results suggest that body movements in younger fetuses do not occur with accelerations that are readily recognizable (i.e., less than 15 bpm), but as fetuses get older, the interaction between body movements and fetal heart rate becomes more evident and accelerations become more recognizable (i.e., greater than or equal to 15 bpm). The data presented suggest that there is a maturational aspect to the relationship between fetal heart rate and fetal body movements as fetuses increase in gestational age from 24 to 32 weeks. The conclusion, therefore, is that the nonstress test, as presently defined for older fetuses, is not valid for gestations below 32 weeks, and new criteria must be established.     

The extent of fetal heart rate accelerations associated with fetal body movements in relation to the duration of fetal body movement

The temporal relations between fetal body movements and associated fetal heart rate accelerations were shown as the ratios of duration of acceleration or acceleration amplitude and the duration of associated fetal body movements in 44 normotrophic and 40 hypotrophic fetuses (body weights within the 6th to 10th percentiles, n = 19, and less than or equal to the 5th percentile, n = 21) between the 36th and 40th gestational weeks. Related to the duration of associated fetal body movements, hypotrophic fetuses proved to have gradually smaller heart rate accelerations than normotrophic fetuses. Moreover, the acceleration parameters duration and amplitude were dependent on the relative duration of fetal body movements. Short fetal body movements were accompanied by fetal heart rate accelerations of relatively highest degree and vice versa. As a consequence, no comparison is possible between temporally different fetal body movements and their associated heart rate accelerations. Of the two acceleration parameters duration and amplitude, the inclusion of the accelerations amplitude in the above mentioned ratio yielded the most obvious results. Taking into consideration that fetuses with intrauterine growth retardation are often in a state of chronic hypoxia, the ratios of acceleration amplitude and durations of associated fetal body movements indicated different degrees of this metabolic situation.     

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).     

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.     

Qualitative description of cardiogram potentials of fetal body and respiratory movements in the non-contracting uterus

Cardiographic reflections of fetal movements were assessed using cardiogram synchronous ultrasonic examination in 44 normotrophic and 40 hypotrophic fetuses with body weights less than or equal to 10th percentile. The study showed that 90% of the fetal body movements were associated with accelerations in fetal heart rate. The degree of associated accelerations depended on the duration of the fetal body movements. In the hypotrophic fetuses the associated heart rate accelerations had a lower amplitude and a relatively longer duration. In impaired fetuses body movements were associated with decelerations in heart rate. Fetal respiratory movements resulted in an increasing beat-to-beat variability in the CTG. This effect did not occur constantly. During prolonged fetal respiratory segments no fetal body movements were observed and vice versa. Possible causes for the association between fetal movements and cardiogram are discussed.     

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.     

Prediction of infection complicating premature rupture of the membranes by monitoring fetal breathing movement with ultrasound

Modified Vintzileos monitoring skill and scoring criteria of fetal biophysical profile (FBP), were used in assaying 48 patients with premature rupture of the membranes (PROM). The last determination before delivery was compared with the outcome of pregnancy. The results showed: (1) The infection rate in patients with low biophysical score (less than or equal to 7) was significantly higher than that of high score (greater than 7); (2) The infection rate in patients presenting fetal breathing movements (FBM) of greater than or equal to 60 sec. It was significantly lower than that in patients with a FBM of less than 60 sec. Infection was almost absent when FBM was present; (3) Fetal distress and neonatal asphyxia could be well predicted by FBP scoring in labor. The above suggested that FBP Scoring FBM is useful in prediction infection and the outcome of babies in patients with PROM.     

Patterns of human fetal heart rate accelerations from 26 weeks to term

Computerized analysis of the distribution of 2598 fetal heart rate accelerations in 83 healthy fetuses at 26 to 40 weeks' gestation demonstrated that the currently used definition of an acceleration as greater than or equal to 15 beats/min for greater than or equal to 15 seconds is applicable only after 30 weeks' gestational age in fetuses with a basal fetal heart rate of less than or equal to 128 beats/min. A significant negative correlation was found between the mean hourly basal fetal heart rate and the mean amplitude of fetal heart rate accelerations from 30 weeks to term. There was also a significant maturational process in the pattern of fetal heart rate and fetal heart rate accelerations that occurred between 26 and 28 and between 30 and 32 weeks; this was characterized by a decrease in basal fetal heart rate, an increase in the amplitude of fetal heart rate accelerations, and an increase in long-term fetal heart rate variability.     

Fetal breathing movements and maternal exercise.

Earlier statements that fetal breathing movements (FBM) are sensitive to changes in the fetal homeostasis prompted the study of the effect of maternal exercise on FBM and fetal heart rate. Forty women in the last trimester of gestation were subjected to a work load (80 W) for 5 min on a bed ergometer cycle; in 30 of them FBM were recorded by A-mode ultrasound, and in 10, the fetal heart rate was monitored by continuous ultrasound. Maternal blood pressure, pulse rate, blood pH and pCO2, and transcutaneous pO2 were also followed. The FBM showed a transient marked increase in incidence immediately after the end of the exercise. No changes in basal level or in baseline variability of the fetal heart rate were found in the recovery period after work. Some possible causes of the observed FBM alterations are discussed. The findings imply that, after this particular form of stress, FBM are a more sensitive indicator of the physiological state of the fetus than the fetal heart rate.     

The influence of maternal hypnosis on fetal movements in anxious pregnant women

The influence of maternal hypnotherapy on fetal body movements in anxious parturients was studied in 25 patients at 35-37 weeks of gestation. There were two groups of patients. Group A consisted of 16 parturients who performed self-hypnosis. Group B consisted of 9 parturients in whom hypnosis was induced by a physician. When compared to a control period of 30 min there was a significant increase in the duration of fetal body movements recorded by ultrasound during 30 min of maternal hypnosis, p less than 0.005 for group A and p less than 0.01 for group B. It is suggested that in anxious parturients fetuses move into a more active state when maternal relaxation is achieved by hypnotherapy.     

The relationship between gestational weeks and fetal breathing movements in each pattern of the fetal heart rate

Fetal breathing movement (FBM) was analysed in each fetal heart rate (FHR) pattern and the gestational 2 weeks. FHR pattern was divided in automated FHR analysis into 3 groups; active, intermediate and resting patterns. The patients consisted of 102 pregnant women at 30-41 weeks, including 13 complicated pregnancies. 1) The active pattern percentage was 52.7% at 32-33 weeks and it decreased gradually. That of the resting pattern was 25.5% at 32-33 weeks and it increased gradually. 2) The percentages of positive FBM in the active pattern were significantly larger than those in the resting pattern in each 2 weeks. 3) The duration of continuous FBM ranged from 3 to 202 sec. FBM of long duration tended to exist in the resting pattern rather than in the active pattern. 4) The percent time ratio of FBM ranged from 1.0 to 92.7% and showed no definite relationship with the FHR patterns or gestational weeks. 5) The FBM rates in each FHR pattern showed no significant differences. Their sequential differences after 36 weeks were significant; that is, FBM in the resting pattern was more regular than that in the active pattern. 6) In high risk pregnancy, the resting pattern percentage was 52.3% and the ratio of positive FBM in the resting pattern was significantly smaller than that in active pattern.     

Fetal body and breathing movements as predictors of intraamniotic infection in preterm premature rupture of membranes

A prospective study of fetal behavior in cases complicated with preterm premature rupture of membranes was conducted in 41 patients. The length of time and the number of fetal breathing and gross body movements were correlated with the amniotic fluid culture results. An episode of fetal activity (body movements and breathing movements) of greater than or equal to 30 seconds during 30 minutes of observation was associated with the absence of intraamniotic infection in 100% of the cases. On the other hand, the absence of fetal breathing movements and gross body movements of less than a 50 second duration during 30 minutes of observation was associated with positive amniotic fluid cultures in all cases. If an episode of fetal breathing movements was present but lasted less than 30 seconds and/or the total time of gross body movements was greater than 50 seconds, 64% of patients had an intraamniotic infection.     

The rate and regularity of breathing movements in the normal and growth-retarded fetus

The rate and regularity of fetal breathing movements (FBM) were determined in 14 women with uncomplicated singleton pregnancies, eight of whom were between 30 and 33 weeks gestation and six between 37 and 40 weeks gestation. Similar observations were made in 19 women with pregnancies complicated by severe intrauterine growth retardation, 11 of whom were between 30 and 33 weeks and eight between 37 and 40 weeks. In normal pregnancy recordings of breath-to-breath intervals showed that FBM became more regular with advancing gestational age, and the rate [breaths/min, mean (SEM)] slowed from 57.2 (1.3) at 30-33 weeks to 47.9 (0.8) at 37-40 weeks. FBM in the growth-retarded group were regular at each gestation studied and the rate was even slower than in the normal group at term, being 41.9 (1.2) at 30-33 weeks and 41.1 (1.0) at 37-40 weeks. Hyperoxia and hypercapnia appeared to have no consistent effect on fetal breathing rate. Fasting for greater than 12 h considerably reduced the rate of FBM in the normal fetus but only marginally so in those with growth retardation. It is concluded that the pattern of FBM provides more information about the fetus than the amount of time spent breathing, particularly when growth is retarded.     

Description of cardiogram potentials of fetal movements in labor

Examples of cardiographic reflections of intranatal fetal movements (body movements) in 130 normotrophic and 26 hypotrophic fetuses (body weight less than or equal to 10th percentile) are presented. Labour-synchronous accelerations of fetal heart rate occurred in 95% associated with fetal body movements. About 83% of the body movements associated with fetal heart rate accelerations occurred periodically. Strikingly, labour with fetal body movements resulted in accelerations, whereas labour alone hardly ever produced medium-term heart rate changes or variable decelerations. In contrast to periodical accelerations with associated body movements, periodical accelerations without associated fetal body movements, which are mainly of hemodynamic origin, indicated potential fetal risk. Even with medium-degree or severe variable decelerations in the expulsive period, fetal body movements with associated heart rate accelerations indicated a good actual fetal condition. The importance of cardiogram synchronous real-time ultrasonic examination of intranatal fetal movements is discussed.     

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.     

Intrapartum fetal activity

Fetal activity throughout pregnancy has been thoroughly studied. Relatively little informations regarding intrapartum fetal activity is available. Richardson et al. [8] found no fetal respiratory movements. While Boylan et al. [2] and Whittman et al. [12] reported decreased fetal breathing movements in active labor. This study was undertaken to evaluate the normal pattern of fetal activity in labor. Fetal movements (FM) and fetal breathing movements (FBM) were monitored by realtime ultrasound during active labor at term. The incidence of FM and FBM were measured in 18 fetuses. Results were correlated with simultaneous fetal heart rate (FHR) changes, postpartum cord blood pH and Apgar score. Recordings were made for one hour on every patient. The mean percentage incidence (PI) of FM was 19.5 per cent (range: 10.1-28.6 percent) and FBM was 8.5 per cent (range: 0-27 percent). All FM were associated with FHR accelerations, stronger movements were associated with higher FHR accelerations. No FHR accelerations were observed with FBM alone, unless accompanied by fetal movement. The lowest PI of total fetal activity (TFA, i.e. FM plus FBM) was 12.1 per cent. Movements decreased as labor progressed, while FBM remained unaltered. All newborns had cord venous blood pH of greater than 7.25 and Apgar scores of greater than or equal to 7, at five minutes. Our data suggest that in the normal uncompromised fetus, FM and FBM continue during labor at term. However, while FM tends to decrease as labor progresses. FBM tends to be constant throughout labor. This finding might indicate the autonomous nature of FBM.(ABSTRACT TRUNCATED AT 250 WORDS)     

Movement and heart acceleration behavior of eutrophic fetuses in the early and late dilatation period

The degree of fetal respiratory and body movements as well as of fetal heart rate reactivity was checked by synchronous ultrasonic and cardiographic monitoring of 18 normotrophic fetuses in the early and late dilation period. Apart from the fetal respiratory movements, which could no longer be observed in the late dilatation period, the degree of fetal body movements remained unaffected during the birth process. In the late dilatation period, the mean amplitude of heart rate accelerations occurring in association with fetal body movements was significantly lower than in the early dilatation period. In the unimpaired normotrophic fetus, however, the reactivity of the fetal cardiovascular system increased during the birth process in relation to the ratio of the amplitude of heart rate accelerations and the duration of associated fetal body movements. Hence, a decrease in fetal heart rate reactivity signals intranatal disturbance of the materno-utero-placento-fetal entity.     

The effect of betamethasone and dexamethasone on fetal heart rate patterns and biophysical activities. A prospective randomized trial.

BACKGROUND; Contradictory findings on the effect of betamethasone versus dexamethasone on antenatal tests of fetal well-being have been reported. The purpose of this study was to compare the effects of these steroid compounds on fetal heart rate patterns and biophysical activities in a prospective. randomized trial. STUDY DESIGN: Forty-six pregnant women (gestational age range 27-34 weeks) at risk for preterm delivery were randomized to receive betamethasone or dexamethasone for enhancement of fetal lung maturity. Fetal heart rate was recorded for 60 minutes and analyzed with the Sonicaid System 8000 before (0 hours), and 48 hours and 96 hours after steroid administration. Subsequently, fetal limb, body and breathing movements were sonographically observed and quantified for 30 minutes. To account for fetal circadian rhythms, all examinations were performed between 1 p.m. and 5 p.m., at least one hour after maternal meals. RESULTS: Fetal heart rate accelerations (p<0.001; p<0.01), short-term variation (p<0.0001; p<0.05), long-term variation (p<0.01; p=NS), duration of high episodes (p<0.001; p<0.05), total movement count (p<0.001; p<0.05), and duration of breathing time (p<0.0001; p<0.0001) were substantially reduced 48 h after betamethasone and dexamethasone administration, respectively, with percent reduction being larger for the betamethasone group, except for breathing movements (p<0.05; p<0.001; p<0.001; p<0.005; p<0.05; p=NS; respectively). In 68.2%( and 45.5% of fetuses, less than 30 seconds of continuous breathing movements were found in the betamethasone and dexamethasone groups, respectively. In 71.8% and 12.5%, of fetuses, respectively, less than 2 body/limb movements were observed. Therefore five and two fetuses in the betamethasone and dexamethasone study group, respectively, had both nonreactive fetal heart rate monitors for 60 minutes and biophysical profiles of < or =4/10. All parameters returned to baseline values at 96 h. Baseline fetal heart rate and numbers of decelerations remained unchanged (p=NS). CONCLUSIONS: Both betamethasone and dexamethasone induce a profound, albeit transient, suppression of fetal heart rate characteristics and biophysical activities in the preterm fetus. However, the effect of betamethasone is more pronounced. Awareness of these phenomena might prevent unwarranted iatrogenic delivery of preterm fetuses.     

The rate and regularity of breathing movements in the normal and growth-retarded fetus

Summary. The rate and regularity of fetal breathing movements (FBM) were determined in 14 women with uncomplicated singleton pregnancies, eight of whom were between 30 and 33 weeks gestation and six between 37 and 40 weeks gestation. Similar observations were made in 19 women with pregnancies complicated by severe intrauterine growth retardation, 11 of whom were between 30 and 33 weeks and eight between 37 and 40 weeks. In normal pregnancy recordings of breath-to-breath intervals showed that FBM became more regular with advancing gestational age, and the rate [breaths/min, mean (SEM)] slowed from 57.2 (1.3) at 30–33 weeks to 47.9 (0.8) at 37–40 weeks. FBM in the growth-retarded group were regular at each gestation studied and the rate was even slower than in the normal group at term, being 41.9 (1.2) at 30–33 weeks and 41.1 (1.0) at 37–40 weeks. Hyperoxia and hypercapnia aeared to have no consistent effect on fetal breathing rate. Fasting for >12 h considerably reduced the rate of FBM in the normal fetus but only marginally so in those with growth retardation. It is concluded that the pattern of FBM provides more information about the fetus than the amount of time spent breathing, particularly when growth is retarded.