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.     

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.     

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.     

Fetal movement and acceleration behavior in hypertension in pregnancy

Under standardized conditions, 26 pregnant women with pregnancy-related hypertension of different degrees were submitted to cardiogram-synchronous recording of fetal body and respiratory movements. The gestational age was between the completed 34th and 38th weeks. Of the 26 fetuses of the risk group, 20 were normotrophic and 6 hypotrophic. 40 normotrophic unimpaired fetuses of the same gestational age served as a control group. The average duration of the examination period was 70 minutes. The fetal movement and acceleration behaviours did not differ between the normotrophic fetuses of the risk group and those of the control group. The hypotrophic fetuses from the risk group, however, had significantly lower fetal body and respiratory activities than the normotrophic fetuses from this group. The same holds true for the degrees of heart rate activity. It can be concluded that pregnancy-related hypertension as the only pregnancy complication does not have a measurable influence on fetal movement and acceleration behaviours. This is true for both treated and untreated pregnancy-related hypertensions. The severity of pregnancy-related hypertension is not primarily reflected in changes of fetal movement and acceleration behaviours, either. This means that the parameters presented are not suited to prognosticate the effects of pregnancy-related hypertension on the fetus a priori. The situation becomes quite different if in addition to pregnancy-related hypertension some intrauterine fetal growth retardation develops. In this case, the fetus indicates its impairment by increasingly impaired movement and heart rate activities as a consequence of chronic oxygen deficiency.     

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.     

Duration, amplitude and shape of accelerations in relation to fetal body movements in behavioral state 2F

The relationship between fetal movements and fetal heart rate accelerations was analyzed in 34 healthy near term fetuses. Periods of coincidence 2F (C2F) with a mean duration of 34 +/- 6 minutes per fetus were selected, with a total of 463 accelerations. Nineteen percent of single body movements and 71% of compilations of movements were accompanied by an acceleration. The minimal duration of single movements associated with accelerations was 4-5 seconds. Movements with associated accelerations differed significantly in duration from movements without accelerations. The duration of accelerations was strongly correlated with the duration of movements. The amplitude of accelerations was not clearly correlated with the duration of movements, but depended on the type of movement. The shape of accelerations appeared to be dependent on the timing of the various fetal movements. In 77%, the number of notches in the accelerations was equal to the number of pauses in the movement complications. A discrepancy between notches in accelerations and pauses in movements could be explained in the majority of cases when the timing of the various movements in relation to one another was considered, or by the presence of fetal mouth movements.     

Longitudinal measurements of fetal breathing, body movements, heart rate, and heart rate accelerations and decelerations at 24 to 32 weeks of gestation

Fetal breathing, fetal body movements, fetal heart rate, and fetal heart rate accelerations and decelerations were studied longitudinally in healthy fetuses between 24 and 32 weeks' gestation in the second and third hour following an 800 kcal maternal meal. The expected increase in fetal breathing following a maternal meal was not seen until fetuses were at 30 to 32 weeks' gestation. The number of body movements decreased and the interaction between body movements and fetal heart rate accelerations became more evident as fetuses became older. Fetal heart rate decelerations increased with gestational age, and the relative proportion of total decelerations that were either associated with body movements or were part of a deceleration/acceleration/deceleration complex increased from 24 to 32 weeks' gestation. The data support the hypothesis that gestational age is an important variable to consider when interpreting biophysical measurements in the human fetus at 24 to 32 weeks' gestation. Fetal body movements may be the single most important measurement of fetal health at these gestational ages.     

Quantitative and Qualitative Relationships Between Fetal Heart Rate Accelerations and Fetal Movement

We measured duration, amplitude, and duration at peak amplitude of 117 heart rate accelerations of 12 normal fetuses greater than 36 weeks gestation. Fetal movement measured by Doppler was analyzed for duration of movement; number of limb, spine, and rolling movements; and total movements per epoch of movement. Of 117 accelerations, only five were not associated with recorded movement and all of these had amplitude less than 12 bpm and duration less than 16 seconds. Only four (3%) accelerations occurred before fetal movement was detected, 23 (20%) began after onset of movement, and the large majority (77%) of fetal heart rate (FHR) accelerations occurred synchronously with fetal movement. In addition to an obvious correlation between number of movements and time spent in movement, a relationship exists between movements and duration of accelerations. Movements do not correlate with amplitude of accelerations. Fetal movement and heart rate acceleration relate temporally, but the strength or type of movements does not affect the amplitude of accelerations. This supports the argument that FHR accelerations are not directly mediated by quantity or quality of fetal movement, but that either all or none of the responses or central mechanisms are involved.     

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.     

The relationship between uterine contractions, fetal movements and fetal heart rate patterns in the active phase of labor

The relationship between fetal movements, fetal heart rate and uterine contractions was studied with a computerized system in 18 parturients during the active phase of labor. 80% of FHR accelerations and 39% of uterine contractions were associated with fetal trunk movements. The probability of association was greater in longer movements and larger accelerations. 98% of fetal movements which lasted 10-15 s, 98% of accelerations with an amplitude of 25-30 bpm and 96.4% of accelerations with a duration of 40-50 s were associated with fetal trunk 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.     

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.     

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.     

Percent acceleration time: a new method of fetal assessment

The percent acceleration time (PAT) is a fetal heart rate parameter, which may be derived from the nonstress test (NST). It is based on measurement of the duration of individual movement-associated fetal heart rate accelerations (MAFAs), obtained during a nonstress test, and is calculated by the formula: (formula, see text) The authors studied 148 fetuses undergoing four or more serial nonstress tests who were delivered within one week of their last test. Percent acceleration time of fetuses with normal outcomes had a mean value of 15.5 +/- 10.0 (SD)%, correlated well with the frequency and amplitude of movement-associated fetal heart rate accelerations but was independent of gestational age and mean baseline fetal heart rate. No normal fetus had a percent acceleration time of less than 5% on its last nonstress test, while only one abnormal fetus had a percent acceleration time that exceeded the mean percent acceleration time of the normal group. All abnormal fetuses had a significant progressive decline in percent acceleration time (mean: 50.6%). Percent acceleration time values were more sensitive in identifying fetuses with perinatal compromise than were conventional criteria for nonstress test reactivity, and may provide a useful alternative to assessment of fetal status when other quantitative methods are unavailable (continuous ultrasound visualization) or less reliable (maternal perception, tokodynamometry, palpation).     

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.     

Heart rate variation and movement incidence in growth-retarded fetuses: the significance of antenatal late heart rate decelerations

In 37 intrauterine growth-retarded fetuses, combined 1-hour recordings of fetal heart rate and body movements were made within 24 hours of elective cesarean section. Fetal body movements were recorded simultaneously by use of real-time ultrasound. The study group was divided into two subgroups, according to the presence (n = 29) or absence (n = 8) of antepartum late heart rate decelerations. Correlations were made with umbilical blood gas values obtained immediately after cesarean section. Baseline heart rate variation was reduced below the normal range in 88% of the intrauterine growth-retarded fetuses with decelerations but in only 37% of the group without decelerations. A reduction in fetal heart rate accelerations and body movements and an increase in mean heart rate also were observed only in the group with decelerations. Late heart rate decelerations were associated with low PO2 values in both umbilical artery and vein. It is concluded that in intrauterine growth-retarded fetuses reduced heart rate variation and movement incidence correlate with the presence of late heart rate decelerations before birth and with hypoxemia at birth.     

Fetal heart rate patterns in the small-for-gestational-age human fetus

A total of 24 pregnant women with growth-retarded fetuses were studied to examine the distribution of fetal heart rate accelerations between 30 and 40 weeks' gestation, as compared with those of fetuses of normal growth that were matched for gestational age and length of fetal heart rate tracings. Growth-retarded fetuses had significantly lower PO2 levels in the umbilical artery at birth (3 mm Hg less) than did healthy fetuses (p less than 0.05), but without metabolic acidosis. There was a larger proportion of small amplitude (less than 10 beats/min) and a smaller proportion of large amplitude (greater than 20 beats/min) fetal heart rate accelerations in the small-for-gestational-age fetuses than in the fetuses of normal growth. Although the number of accelerations was significantly reduced (50% less) in growth-retarded fetuses compared with healthy fetuses, there was no significant difference in the mean basal fetal heart rate and the mean number of decelerations between the two groups. Currently used definition of an acceleration as greater than or equal to 15 beats/min for greater than or equal to 15 seconds was applicable only in fetuses of normal growth. We hypothesized that a decrease in absolute acceleration frequency might be a useful index to detect the chronically hypoxemic fetus before severe metabolic acidosis and irreversible damage occurred.     

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 effect of induced maternal hypercapnia on gross fetal body movements

Gross fetal body movements and fetal heart rate were studied serially during the last trimester of pregnancy by real-time ultrasound in 11 healthy women during the inhalation of 4% carbon dioxide in air. We observed that induction of maternal hypercapnia during the last 10 weeks of pregnancy had no effect on the percentage of time of gross fetal body movements or on fetal heart rate accelerations.     

Characterization of fetal body movement recorded by the Hewlett-Packard M-1350-A fetal monitor.

OBJECTIVE: The purpose of this study was to evaluate the ability of a commercially available monitor, the Hewlett-Packard M-1350-A fetal monitor, to record and discriminate between various fetal body movements. STUDY DESIGN: Twenty-four patients between 29 and 42 weeks' gestation were monitored over a 20 to 30 minute period simultaneously by the Hewlett-Packard instrument and ultrasonography. RESULTS: All 593 single or clustered fetal movements recorded by the monitor were seen ultrasonographically as being extremity movements that were either isolated or combined with trunk motion. Discriminating between these two types of movements was not possible on the basis of the duration of recorded movements. All adequate fetal heart rate accelerations were attributed to combined trunk and extremity movements. Detection of fetal hiccups was less exact, and recording of fetal hand, mouth, breathing, and rapid eye movements was beyond the sensitivity of the monitor. Signal artifacts were attributable to either motion of the maternal abdomen or Doppler transducer and became less of a problem with experience. CONCLUSION: Fetal extremity movements were recorded with accuracy by this new fetal monitor.