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
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
http://www.baillement.com
mystery of yawning 
 
resolutionmini

mise à jour du
24 novembre 2012
Plos One
2012;7(11):e50569
Development of Fetal Yawn Compared with Non-Yawn Mouth Openings from 24&endash;36 Weeks Gestation

Nadja Reissland, Brian Francis, James Mason

Chat-logomini

Tous les articles consacrés au bâillement foetal
Fetal yawning: all publications
 
Bâillements du foetus: la naissance d'un comportement
révèlée par l'échographie 4D
 
Video de bâillement foetal à 23 semaines en Echo 4D
Video de bâillement foetal à 13 semaines en Echo 4D
 
Sonography Edited by: Kerry Thoirs
Fetal Yawning Olivier Walusinski
Chapter 18 Pages 325-332
 
Piontelli A. Fetal Yawning in Development of Normal Fetal Movements. The fisrt 25 weeks of gestation. Spinger. 2010. 135p.

Introduction
 
The development of yawning, a movement which has been reported in humans and many vertebrates from fetal stages to old age remains poorly understood [3]. According to Provine [4] human are unique because in contrast to other species, for example rats, where males yawn more frequently than females [5], in humans both sexes yawn equally often. There is however, a lack of research on fetal yawning.
 
Research suggests that there is a U-shaped developmental progression to yawning in that premature infants yawn more frequently than term babies [6] and primary school children yawn more frequently than kindergarten children [7]. Most research on yawning, a movement defined as mouth opening with the jaw dropping, relates to the contagious nature of yawning. Provine [4] suggests that yawns are so infectious that simply thinking or reading about yawning results in a yawn in around 60% of observations [8]. Interestingly, children are immune from the contagious nature of yawning until around five years of age [9] hence not only yawning frequency but also the social context of yawning, such as contagious yawning, has a developmental component which is as yet unexplained. Contagious yawning however cannot be the reason for fetal yawning. Another theory which potentially explains fetal yawning suggests that yawning is related to central nervous system (CNS) arousal modulation and hence related to waking motility patterns [6]. This is supported by evidence that cortisol levels are increased during stress and fatigue as well as yawning [10]. However, others disagree arguing that fetuses do not yawn because they feel sleepy'' [11 p: 36]. Even though the relationship between the neural network of mouth, tongue and respiratory movements is not well understood, some research suggests that the function of yawning in fetuses might lie in activity-dependent brain maturation [12].
 
In summary, yawning has been reported from the end of the first trimester, [1]. Sherer, Smith, & Abramowicz [13] described yawning in a case study at 20 weeks gestation. Roodenburg, Wladimiroff, van Es, & Prechtl [14] observed 9 fetuses in 2D imaging who only occasionally yawned but they were able to ascertain that jaw movements increased up to 28 weeks and then declined. Yigiter, & Kavak, [15], in a cross sectional study, report no significant changes in mouthing, yawning and sucking. One reason for varied findings could be due to a lack of a precise definition of yawns compared with mouth opening. McMagnus, Devine, & Brandsetter [16] go so far as to argue that definitions of yawning are so varied that what has been labelled a yawn can be just a mouth opening or repeated set of mouth openings rather than yawns. Indeed, in terms of a measure of fetal neurological development [17], yawning and mouth opening are not distinguished. Provine ([4] p532) suggests a general definition of a yawn consisting of jaws open in a wide gape, a deep inward breath followed by a shorter exhalation and a closing of the jaws. Robust differentiation between wide mouth opening and a yawn in contrast requires a dynamic definition of yawning [18]. Hence, it is essential to differentiate between wide mouth opening with the jaw dropping and yawning in terms of the timing of these mouth movements either being labelled a yawn or mouth stretch. One dynamic definition proposed by Petrikovsky, et al. [18] is a ''prolonged wide opening of the mouth followed by a quicker closure of the mouth''. Petrikovsky et al. [18] used this definition of yawning in 2-D ultrasound examinations of fetal mouth movements. Applying this dynamic definition to their data they found a mean of 5 yawns in 18 of 22 healthy fetuses. In contrast, the nine anaemic fetuses studied yawned more frequently with a mean of 12 yawns observed in the 1 hour period. The present longitudinal study examined the dynamics of yawning compared with non-yawn mouth opening in 15 healthy fetuses, 8 girls and 7 boys, observed four times over the second and third trimester of pregnancy. We expected that if yawning is a developmental process, then the frequency of yawning might change during gestation. Given previous research on human yawning we also did not expect to identify sex differences.
 
Discussion and Conclusion
 
There are a number of hypotheses explaining the ubiquitous behaviour of yawning [24]. One of them is that yawning is a response to elevated levels of carbon dioxide or depressed levels of oxygen in the blood which has been shown to be a false association [2]. The results of this study demonstrate that yawning can be observed in healthy fetuses and replicates previous studies with 2-D images. In contrast to previous research we could also show that although healthy fetuses vary in the frequency of yawns observed overall, the repeated measures design allowing an observation of the same fetuses at 24 to 36 weeks gestation in 4 weekly intervals showed that in healthy fetuses the frequency of yawning declines over time. Specifically, in our longitudinal study following 15 fetuses, we observed yawns when the fetus was active at 24 weeks but not in the similarly active fetus at 36 weeks (Figure 3). This finding corroborates work by Giganti et al. [6] who videotaped 12 healthy infants ranging in age from 31 to 40 weeks (post gestational age) and recorded 1.10+20.7 yawns for the infants in a 24 hour period which decreased with age to zero yawns.
 
Hence, this research could support the suggestions that yawning is related to CNS maturation e.g. [25&endash;26] rather than arousal modulation. Furthermore, supporting other results on similar yawning frequency in human males and females, in our research we did not find any sex differences in yawning frequency. In summary, the importance and function of yawning is still unclear. Some researchers found an association of yawning with neurological functioning e.g. [25&endash;27]; others found a relationship between yawning and Parkinson's disease [28]. Yet other research argued that yawning has a thermo-regulative function [29]. A further hypothesis states that blood cortisol levels might be the cause for yawning [30] or that yawning could be due to the increase of venous blood to the heart of the fetus [18]. A developmental function of yawning could be related to jaw movements, which are important in the prenatal and postnatal development of the cartilage in the temporo-mandibular joint, enabling normal mouth movements [31]. In contrast to these medical reasons for yawning others argue that yawning has a communicative function [32]. In our sample, we can exclude the communicative function of yawning. However, other hypotheses could be supported. Given that the frequency of yawning in our sample of healthy fetuses declined from 24 to 36 weeks gestation, it is possible that yawning and simple mouth opening have a maturational function early in gestation. Although, yawning and simple mouth opening have the same trajectory shape over age it is notable that the yawning rate is just over double the nonyawning rate. In order to exclude the potential function of cortisol in yawning, in future research it would be important to measure maternal cortisol levels at the time of observing fetal yawns.