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La parakinésie brachiale oscitante
Yawning: its cycle, its role
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Fetal yawning assessed by 3D and 4D sonography
Le bâillement foetal
Le bâillement, du réflexe à la pathologie
Le bâillement : de l'éthologie à la médecine clinique
Le bâillement : phylogenèse, éthologie, nosogénie
 Le bâillement : un comportement universel
La parakinésie brachiale oscitante
Yawning: its cycle, its role
Warum gähnen wir ?
 
Fetal yawning assessed by 3D and 4D sonography
Le bâillement foetal
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mystery of yawning 

fetal yawn

mise à jour du
3 décembre 2006
J Matern Fetal Neonatal Med
2006;19(11):707-721
Normal standards of fetal behavior
assessed by four-dimensional sonography
Yigiter AB, Kavak ZN.
Fetal Medicine Unit, Department of Obstetrics and Gynecology, Marmara University
School of Medicine, Haydarpasa, Istanbul, Turkey
 
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Abstract:
Objective. In this prospective randomized study, fetal behavior was investigated in order to determine the standard parameters of fetal movements and facial expressions in all three trimesters of normal pregnancy.Methods. Sixty-three pregnant women with singleton pregnancies in all trimesters were included in the investigation. Four-dimensional (4D) ultrasound was performed for each patient over a 30-minute period. Variables of maternal and fetal characteristics including gestational age, eight fetal movement patterns in the first trimester, and sixteen parameters of fetal movement and fetal facial expression patterns in the second and third trimesters were recorded for the construction of fetal neurological charts.
 
Results. In the first trimester, a tendency towards an increased frequency of fetal movement patterns with increasing gestational age was noticed. Only the startle movement pattern seemed to occur stagnantly during the first trimester (p > 0.05). At the beginning of the second trimester, the frequency of fetal movement patterns tended to increase. During the second and third trimester, multiple regression and polynomial regression revealed statistically significant changes in tongue expulsion (p < 0.05), smiling (p < 0.05), grimacing (p < 0.05), swallowing (p < 0.05), eye blinking (p < 0.01), head movements, and all hand to body contact movements (p < 0.01), except for head anteflexion (p > 0.05).
 
There were no statistically significant changes during the second and third trimesters in mouthing, yawning, and sucking (p > 0.05). At the middle of the third trimester, the fetuses displayed decreasing or stagnant incidence of fetal facial expressions except for eye blinking, which showed increased frequency with increasing gestational age. A statistically significant correlation was found between all head movements and hand to body contact patterns during the second and third trimesters except for head anteflexion (r = -0.231; p > 0.05).
 
Conclusions. The full range of quantitative fetal facial expressions and fetal movement patterns can be assessed successfully by 4D sonography. It is important to be able to assess normal fetal behavior throughout gestation to identify abnormal behavior before birth
 
fetal yawning
 
Introduction
Understanding the structure and function of the fetal nervous system has been a dream of physicians for centuries. The number of studies showing that many neurological problems, such as minimal cerebral dysfunction, schizophrenia, epilepsy, and autism, result at least in part from prenatal neurodevelopmental problems is increasing.
 
Fetal behavior can be defined as any observable action or reaction (to an external stimulus) by the fetus. This may be recorded by maternal perception of movement or real-time ultrasound imaging by means of which fetal behavior can be observed in the clearest and most detailed way. Innovations in ultrasonic technology have created new possibilities in the study of feta behavior. The introduction of four-dimensional ultrasound (4D US) has led to very important conclusions concerning fetal behavior by enabling us to produce measurable parameters for the assessment of normal neurobehavioral development . It is now possible to study a full range of facial expressions including smiling, crying, scowling, and eyelid movements in almost real-time by 4D US.
Analysis of the dynamics of fetal behavior has led to the conclusion that fetal behavioral patterns directly reflect developmental and maturational processes of the fetal central nervous system. As we learned from postnatal studies of neonatal behavior, assessment of behavior is a better predictor of neurodevelopmental disability than neurological examination. These findings implicated that understanding the relation between fetal behavior and developmental processes in different periods of gestation would make possible the distinction between normal and abnormal brain development, as well as the early diagnosis of various structural or functional abnormalities.
 
The preliminary results of multicentric studies of fetal brain function suggest that the study of fetal behavior should be standardized as much as possible. If behavioral analysis is to have a role in the routine clinical environment, then normal standard parameters and objective methods need to be developed. De Vries and colleagues were the first to provide a systematic and detailed classification and quantitative longitudinal analysi of fetal behavior during the first half of pregnancy using two-dimensional ultrasound (2D US).
 
During the past three years, Kurjak et al. have initiated extensive research into fetal behavior in normal and pathological pregnancies by both threedimensional (3D US) and four-dimensional ultrasound (4D US).
This study reports reference ranges with gestational age for suggested use as fetal neurobehavioral development parameters in normal singleton pregnancies. Standard movement pattern and facial expression pattern curves have been constructed for all trimesters of pregnancy.
fetal yawning
In the first trimester using 4D US one can simultaneously assess movements of the fetal head, body, and all fou extremities in three dimensions. Therefore, the earliest phases of the human anatomical and motor development can be visualized and studied simultaneously . It is possible to study total fetal facial activities by 4D US. In addition to yawning, sucking, and swallowing described by 2D real-time imaging, it is now possible to study a full range of facial expressions including smiling, crying, and eyelid movements with this technology.
 
Furthermore, four-dimensional sonography seems to be the method of choice for detecting subtle changes such as superimposed rotations and changes in direction of the movements. The first spontaneous fetal movements can be observed at postconceptional weeks 7 to 7.5. In the subsequent weeks (8th to 9th weeks of gestation), they are replaced by various well-organized general movements, which include head, trunk, and limb movements, as well as with the isolated limb movements. Hands become sensitive at 10.5 weeks and lower limbs begin to participate in these reflexes at approximately the 14th week.
 
In our study, among eight movement patterns studied in the first trimester, general movements followed by isolated hand movements were the most frequent movement patterns. We observed a tendency towards an increased frequency of fetal movement patterns with increasing gestational age. These findings are in agreement with the literature. General movements are the first complex fetal movement patterns observable by 2D US.
 
According to Prechtl these are gross movements, involving the whole body. They can be recognized from 8 to 9 weeks of pregnancy and remain present until 16&endash;20 weeks after birth. Some of the movement patterns could not be observed through all trimesters. For example, startleand stretching, which were observed in the first trimester, disappear with the progression of pregnancy. As the pregnancy progresses, the random movements of the fetalbody, which are the earliest signs of fetal activity, change into the well-organized behavioral patterns. Only a few studies are available on fetal movement patterns during the second trimester. De Vries and colleagues studied fetal movements from 20 and from 24 postmenstrual weeks onwards. During the secon trimester of pregnancy, the incidence of body movements increased considerably. Kurjak et al. recently reported the first study that described the 4D US techniques used for obtaining longitudina standard parameters of fetal neurological development in all trimesters of a normal pregnancy.
 
They found a tendency towards an increase in the frequency of fetal movement patterns at the beginning of the second trimester by 4D US. However, all types of head movements and hand to body contact movements indicated a decrease in frequency from the beginning of the second trimester to the end of the third trimester. Our results are similar to this study, as we found a significant correlation between all head movements and hand to body contact patterns during the second and third trimesters except for head anteflexion, which did not show a significant change during the second half of pregnancy. It has also been suggested that there is a tendency towards decreased frequency of observed facial expressions and movement patterns with increasing gestational age.
 
It has been suggested that the observation of behavioral quality is a better predictor of neurological impairment than neurological examination. In this respect, we are unable to study the quality of facial movements in fetuses, because this parameter has not yet been described. The observation of facial expression may be of scientific and diagnostic value and this scientific approach opens an entirely new field. For example oneof the diagnostic goals of observing facial expressions is the prenatal diagnosis of facial paresis. Criteria for the identification are asymmetrical facial movements and detection of the movements restricted to only one side of the face. In one study, the most frequent fetal and neonatal movements registered in the third trimester and in the neonatal period were scowling, eye and mouth opening, and hand to face, hand to eye, and hand to head movements.

There was a tendency towards a decrease in the frequencies of observed facial expressions (isolated eye blinking, mouthing) and some hand movement patterns (hand to head, hand to mouth, hand to face, hand to eye, hand to ear) with increasing gestational age. Significant trends in fetal eye movement organization can also be observed during the second half of pregnancy, especially during the third trimester [10,21]. The earliest eye movements appear at the 16th to 18th weeks of gestation. At 24 to 26 weeks of gestation, they appear more frequently. At 36 to 38 weeks of gestation, they become integrated with other parameters of fetal activity.

The Zagreb group in another study, evaluated fetal behavioral patterns in the third trimester between 30and 33 weeks of gestation in 10 gravidas. They noted that among facial activities observed by 4D US, simultaneous eyelid and mouthing movements dominate between 30 and 33 weeks of gestation.

However, another study from the same group noted that all types of facial expressions displayed a peak frequency at the end of the second trimester except isolated eye blinking, which increased at the beginning of the 24th week. The fetuses displayed a decreasing or stagnant incidence of fetal facial expression from the beginning of the third trimester.

In the present study, while mouthing, yawning, tongue expulsion, smiling, sucking, and swallowing expressions displayed a peak frequency between the 24th and 32nd gestational weeks similar to the previous reports, grimacing and eye blinking expressions displayed peak frequency between the 28th and 36th weeks and after the 32nd week, respectively. In our study, the fetuses displayed decreasing or stagnant incidence of fetal facial expression at the middle of the third trimester, except for eye blinking, which showed an increased frequency with increasing gestational age. This was not in concordance with the findings of other authors, probably due to a small sample size in our study and different study samples in all trimesters of pregnancy.

The major problem with the study of fetal behavior is that it is very time-consuming. Nevertheless, there is no other means of assessing the function of the central nervous system in utero, and this is needed for the understanding of the hidden information in the neurodevelopmental pathways of the fetal CNS. Only if normal behavior is understood, is it possible to identify abnormal behavior before birth.

Conclusions

Despite all these efforts, it is not yet clear how we might identify the fetuses with more specific cerebral damage. Currently there is no unified neurobehavioral assessment method for the fetus. The goal of all investigations should be to gather information that reveals neural continuity from fetus to newborn. The availability of quantitative standards might be important for the experts, to allow an awareness of normal fetal behavior throughout the whole of gestation in order to assess the neurological condition of the fetus.