The relation between fetal heart rate accelerations and fetal movements

Fetal heart rate (FHR) accelerations associated with fetal movements is considered a sign of fetal well-being. Fetal movements as felt by the pregnant woman and visualized by real-time ultrasonography were correlated to FHR accelerations in 52 normal and high-risk pregnant women. All fetal movements felt by the mother or seen in the real-time ultrasonography were associated with large FHR accelerations (more than 15 beats per minute lasting 15 seconds or more) or small accelerations (fewer than 15 beats per minute). The large accelerations were associated with 78.6% of fetal movements felt by the mother and 99.6% of fetal movements seen by real-time ultrasonography. The small accelerations were associated with 52.9% of fetal movements felt by the mother and 82.4% of fetal movements seen by ultrasonography. Mothers felt 75.7% of fetal movements seen by real-time ultrasonography. It was concluded that fetal movements could be verified by existence of large accelerations on the FHR tracing.     

The relationship between fetal heart rate accelerations, fetal movements, and uterine contractions

The association between fetal heart rate (FHR) accelerations and fetal movements during uterine contractions was studied in 52 pregnant women near term or at the beginning of labor. FHR and uterine contractions were recorded by tococardiograph. At the same time, fetal movements, whether associated or not with contractions, were viewed by real-time ultrasound. During uterine contractions, 95.5% of the FHR accelerations were associated with fetal movements. Also, 90.9% of the accelerations which appeared when the uterus was not contracting were associated with fetal movements. Fetal movements were not seen in 91% of uterine contractions which were not associated with FHR accelerations. The suggestion is made that uterine contractions stimulate both fetal movements and FHR 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.     

Association between fetal movements and uterine contractions in the active phase of labor

Fetal body movements were studied for 40 minutes during the active phase of labor in 15 parturients. The total duration of fetal movements constituted 8.2% of the recording period, with a frequency of 3.8 +/- 2.1 per ten minutes. Of all the movements, 57.3% were associated with uterine contractions, while 40.7% of all uterine contractions were associated with fetal movements. All the fetuses moved in the first 30 minutes of the study period. The fetal movements that were associated with uterine contractions were longer than those not associated with contractions. Similarly, uterine contractions associated with fetal movements were longer than other uterine contractions.     

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.     

Ultrasonic assessment of fetal response to second-trimester amniocentesis

Twenty-three patients undergoing second-trimester amniocentesis were ultrasonically monitored for 30 minutes before and 30 minutes after the amniocentesis. Fetal movements were recorded as movements of limbs, trunk, or combined limb-trunk movements. Fetal heart rates were determined at ten-minute intervals before and after the amniocentesis. No significant increase in total fetal movements, limb movements, trunk movements, or heart rate were found. A significant increase in combined fetal movements was observed. The authors conclude that amniocentesis in the second trimester elicits a change in fetal movement pattern.     

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.     

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.     

Gestational age and fetal biophysical assessment

With improved neonatal care, biophysical assessment to detect fetal asphyxia is used increasingly at an earlier gestational age. We have tested five fetal biophysical variables: nonstress test, fetal breathing movements, fetal movements, fetal tone, and amniotic fluid volume 11,012 times in 5582 singleton fetuses in whom there was a normal perinatal outcome. The nonstress test and fetal breathing movements were more likely to be abnormal at 26 to 33 weeks' gestation compared with 34 to 41 weeks. The nonstress test, fetal breathing movements, fetal tone, and amniotic fluid volume were more likely to be abnormal at 42 to 44 weeks' gestation compared with 37 to 41 weeks. Fetal biophysical tests should be interpreted in relation to gestational age.     

Maternal perception of fetal movements: the optimal duration of a recording period

A regular count of perceived fetal movements by the mother has been proposed as a screening method for the early recognition of fetal distress. Absence or a strongly decreased number of fetal movements during a particular period is considered as a sign of fetal distress. In the study presented, the optimal duration of a recording period for the maternal perception of fetal movements was examined. 186 pregnant patients at gestational ages of 32 and 38 weeks were asked to mark each perceived fetal movement on a time axis for two continuous hours. From these patients an 'optimal' group of 143 pregnancies was selected to constitute the study group. A window technique was applied to the 2 h recordings, searching for periods in which 0, 1 or 2 fetal movements were noted. 23% of the recordings at 32 weeks and 14% at 38 weeks showed absence of fetal movements for at least 30 min. At both 32 weeks and 38 weeks there was absence of fetal movements for more than 1 h in only 1.5% of the recordings. The findings are in agreement with the fetal behavioural state concept. A recording time of 1 h exceeds the normal duration of a fetal quiet-sleep state and minimizes the risk of unjustified suspicion of fetal distress.     

Effect of maternal carbon dioxide inhalation on human fetal breathing movements in term and preterm labor

Induced maternal hypercapnia is a potent stimulus to fetal breathing movements in nonlaboring pregnant women. To determine the effect of maternal CO2 administration on fetal breathing movements during spontaneous labor, 14 healthy pregnant volunteers at term and 34 in preterm labor were recruited. If fetal breathing movements were markedly decreased or absent, the subjects were administered a prepared gas mixture of 3% CO2 in air. In term labor and in true preterm labor, fetal breathing movements were markedly decreased and could not be induced by maternal hypercapnia. Among women with suspected preterm labor, initial absence of fetal breathing movements and failure to evoke this response by maternal hypercapnia predicted delivery within 48 hours with a sensitivity of 80% and specificity of 95.5%. Induced maternal hypercapnia fails to stimulate fetal breathing movements in true term and preterm labor and may assist in distinguishing between true and false preterm labor.     

Subjective recording of fetal movements. II. Screening of a pregnant population; methodological aspects

1914 women were asked to count fetal movements for 15 minutes every evening from the 28th week of pregnancy until parturition. An individual lowest limit for number of fetal movements was calculated from the first five counts. The women were instructed to contact the maternity ward for fetal evaluation as soon as their count fell below the lowest limit on two consecutive evenings (alarm signal). 79% of the women did record fetal movements, the proportion of those who did so being significantly higher in nulliparae and women 20-35 years old than in multiparae, teenagers and women older than 35 years. The mean duration of the registration period was 11.4 (SD 3.2) weeks and the median interval from the end of the registration period to delivery was 0.32 weeks. 31% of the women with an alarm signal on their Fetal Movement Charts never reported the decrease in the fetal movements count. 30% of the women who did report a reduction in the number of fetal movements did so despite the absence of an alarm signal. We conclude that most pregnant women are willing and able to count fetal movements but that they have difficulty in following the instructions concerning when to report a decrease in number of fetal 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.     

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 breathing movements and onset of delivery at term]

It has been studied the relation between fetal breathing activity and labor among 216 patients in uncomplicated pregnancies at term. It has been also described the value of fetal breathing movements in the evaluation of fetal well-being. Among patients where fetal breathing movements were absent 81.9% women delivered within 3 days since ultrasonographic examination. And among patients with visible fetal breathing activity only 25.0% delivered within this period. The analysis of newborn condition based on Apgar score in pregnant women with or without fetal breathing movements showed no significant statistical differences. The absence of fetal breathing movements has no prognostic value concerning the evaluation of fetal well-being in antepartum period. The cessation of fetal breathing activity facilitates to prognose the time of labor in mature pregnancies.     

Subjective recording of fetal movements. I. Limits and acceptability in normal pregnancies

Maternal counting of fetal movements is increasingly used as a clinical method for assessment of fetal health. The present study established normal limits for two methods of subjective fetal movement recording. Four hundred-and-seventeen randomly selected women with low-risk pregnancies recorded the time necessary for 10 fetal movements every morning and also the number of fetal movements during 15 min every evening. The study was carried out between gestational week 34 and parturition. Two hundred-and-twenty-two consecutive women answered a questionnaire after the end of the study. 70% of the women counted fetal movements every day; 66.5% preferred the evening to the morning recording. In a strictly selected normal group (n = 129), no significant change was found in the number of fetal movements or in the time for 10 fetal movements with advancing gestation or approaching parturition. The results of the evening sessions were not influenced by maternal parity, fetal weight, or fetal sex. The great interindividual variation in the results does not allow the application of general normal limits. A method for establishing individual normal low limits for each pregnancy was designed.     

Fetal heart rate monitoring in cases of decreased fetal movement.

Thirty pregnant women in the third trimester of pregnancy in whom fetal movements were reduced up to cessation, for at least 12 hours, were monitored for FHR. The FHR 12-48 hours after the cessation of fetal movements was pathological in 21 cases and normal in 9 cases. The most frequent pathological FHR changes were loss of beat to beat variation and variable decelerations. In the following 48 hours another four cases showed pathological FHR changes. One to four days before the reduced fetal movements only six out of 15 cases showed pathological FHR changes which were L.B.B.V. Meconium was found in only 50% of the cases. It is suggested that pregnant women, especially high risk cases, should record fetal movements as a screening method. FHR monitoring is also a valuable method for detecting antenatal fetal distress, and should be used as an adjunct to fetal movements recording. When acute fetal distress has been established by MAS alone or with FHR change, the fetus should be promptly delivered.     

Effects of acute hypoxemia on fetal movement in the fetal lamb

Chronically instrumented pregnant models were established using 5 Dorset-Rambouillet pregnant ewes with gestational age between 120 and 138 days. Observation of fetal movements were started on the 3rd postoperative day or later when recovery from the surgery to the physiological condition was confirmed by maternal and fetal biophysical parameters. Fetal movements were observed using real-time ultrasound equipment with linear-array transducer placed on the maternal abdomen. Observation encompassed the control period which lasted one hour followed by an experimental period of fetal hypoxemia created by decreasing maternal FIO2. Observation was also continued during the recovery period when the mother was re-exposed to room air. Maternal and fetal samples were periodically obtained during these periods. Frequency of fetal movements was studied in 10 minute periods under the control and hypoxemic conditions. All fetuses exhibited movements during the control period, ranging 1-42 movements/10 minutes, the mean incidence being 16.9 movements/10 minutes. During fetal hypoxemia (average PaO2 decrease: 8.6 mmHg), fetal movements were significantly reduced to 5.5 movements/10 minutes with complete cessation in some cases. In 4 animals which exhibited complete cessation of both fetal movement (FM) and fetal breathing movement (FBM), FBM disappeared before FM, and reappearance of FM was following by FBM during recovery from hypoxemia.     

Fetal movements diagnosed by ultrasound in early pregnancy.

The purpose of this work was to ascertain whether ultrasonic techniques based on fetal movements were suitable for examinations in early pregnancy. The series consisted of 124 patients who came to be examined because of bleeding on the 6th-20th gestational week. The rapid B-scan method detected the fetal movements from the 8th week onwards, and the results were 100% reliable from the 10th week onwards. The combined A-B-scan method detected the fetal movements from the 12th week. Techniques based on the detection of fetal heart function were used as control methods. According to our results, the methods based on the indication of fetal movements constitute a practical alternative for elucidating the problems of early pregnancy.     

Influence of maternal carbohydrate intake on fetal movements at 14 to 16 weeks of gestation

OBJECTIVE: Ultrasonographic assessment of fetal movements at 14 to 16 weeks of gestation before and after maternal oral intake of carbohydrate. DESIGN: Thirty consecutive healthy pregnant women between 14 and 16 weeks of gestation were scanned transvaginally. Real-time ultrasound recordings of 20 min duration were performed in the fasting state and after an oral intake of 110 g of glucose. The number of fetal movements, body and limb movements and breathing movements were evaluated. Fetal movements were quantified using a digital chronometer, and the percentage of time spent moving and the rate of movements per minute were then calculated. Data was statistically analyzed using the simple and Wilcoxon paired t-test. RESULTS: Absolute number of fetal movements, body movements, rotation movements, time spent moving and rate of movements per minute showed a statistically significant increase after maternal intake of carbohydrate (p < 0.0001). CONCLUSIONS: Maternal oral intake of 110 g of carbohydrate significantly increases fetal movements at 14 to 16 weeks of gestation, thus allowing better ultrasonographic viewing of the fetus.