Piontelli
A. Fetal Yawning in Development of
Normal Fetal Movements. The first 25 weeks of
gestation. Spinger. 2010.
135p.
OBJECTIVE: To evaluate the characteristic
patterns of facial expression in fetuses aged
from 28 to 34 weeks using 4-dimensional (4-D)
ultrasonography.
METHODS: The faces of 10 healthy fetuses
aged from 28 to 34 weeks were recorded
continuously for 15 min with a 4-D
ultrasonographic machine performing up to 25
frames per second. The occurrence rates of
blinking, mouthing, yawning, tongue
expulsion, smiling, scowling, and sucking were
evaluated.
RESULTS: Mouthing was the most frequent
facial expression (median, 6.5; range, 2-19)
whereas the least frequent were scowling
(median, 1; range, 0-9) and sucking (median, 1;
range, 0-2). Mouthing was evident in all fetuses
and significantly more frequent than any other
movement (P<.05). Yawning (median, 3;
range, 0-6), smiling (median, 2; range, 0-9),
and blinking (median, 1.5; range, 0-6) were
observed in most cases. Tongue expulsion
(median, 1.5; range, 0-5), scowling, and sucking
were each observed in 6 cases.
CONCLUSION: 4-D sonography provides a means
of evaluating fetal facial expression early in
the third trimester. It may be a key to
predicting fetal brain function and well-being
and an important modality in future fetal
neurophysiologic research
Introduction
Fetal neurobehavioral patterns have been
considered indicators of nervous system
development. Many studies have shown that
normally developing fetuses and fetuses at risk
had different patterns of behavior. For example,
anencephalic fetuses have been found to have
fewer hand and body movements and hydrocephalic
fetuses to have fewer eye movements.
Fetal facial movements, controlled by the
nuclei of facial nerves in the brain, have been
investigated using 2-dimensional (2-D)
ultrasonography. However, it is difficult to
evaluate complex facial activity because of the
anatomic features of the face and the
limitations of this technique.
Only with the appearance of 4-dimensional
(4-D) ultrasonography have a full range of
facial expressions, such as scowling, crying,
and smiling, been observed. To determine whether
there was a fetal facial movement pattern early
in the third trimester, the present study used
4-D sonography to observe 10 healthy fetuses
aged from 28 to 34 weeks.
Discussion
Fetal behavior, defined as any observable
action or reaction to an external stimulus by
the fetus, reflects the activity of the fetal
central nervous system. Insight in fetal
behavior is crucial for the understanding of
normal fetal well-being and in determining
whether a fetus may be compromised. Moreover, a
recent investigation has shown that there is
behavioral continuity from fetal to neonatal
life, which probably includes facial expression
.
The observation of fetal facial expression
may be of diagnostic value in prenatal medicine.
According to previous studies, general fetal
movements can be observed as early as the 8th
week As pregnancy advances, the incidence of
general movements tends to decrease and the
incidence of mouthing tends to increase . At the
34th week, the fetus begins to display some
degree of motor coordination. A link between
fetal eye movements, body movements, and heart
rate pattern, which can be observed from the
25th week on, becomes stable near term .
Regular mouthing and nonrapid eye movement
(state 1) appear at about the same time, from 35
weeks on . The different phases of behavior are
thought to reflect different levels of brain
activity, as fetal habituation may implicate the
function of the cortices . Nonrapid eye movement
sleep may be an indication thalamocortical
pathway function.
Blinking frequency and cognitive state are
related . Also, studies have shown that abnormal
fetuses exhibit different behavior patterns .
With the dev lopment of ultrasonographic
techniques, a great deal of progress has been
made in the evaluation of the fetal face and
behavior and 4-D ultrasonography has
considerable advantages over 2-D and 3-D
ultrasonography in this field of study.
Kurjak and colleagues used 4-D
ultrasonography to study 10 healthy fetuses aged
from 30 to 33 weeks, and found that eyelid and
mouthing dominated at this gestational age .
These investigators also confirmed that there
was a behavioral continuity from prenatal to
postnatal life by studying 10 fetuses aged 33 to
35 weeks , and they concluded that different
facial expressions and movements might represent
fetal awareness .
In the latest study by this team, 100 women
with normal singleton pregnancies were recruited
for longitudinal 4-D ultrasonographic examin
tion to evaluate fetal neurodevelopmental
parameters from the 7th to the 40th week . All
types of facial expression were noted to display
a peak frequency at the end of the second
trimester, except for isolated eye blinking,
whose frequency increases at the beginning of
the 24th week.
A tendency towards decreasing frequency of
facial expressions with increasing gestational
age needs to be demonstrated. In the present
study, a full range of fetal facial expressions
early in the third trimester (from 28 to 34
gestational weeks) were investigated using 4-D
ultrasonographic techniques. As in previous
reports , mouthing was found to be the most
active facial expression during this gestational
period. However, the frequency of blinking,
which in other studies was thought to be similar
to that of mouthing, was lower in this study.
Differences in the characteristics of the
samples recruited and differences in
interpreting the definition of each facial
expression may be reasons for the different
results.
In addition, although the same 15-min period
of observation was used in the present and other
studies, the limitations of such a short period
have been pointed out in the latest
investigation . Extending observation time and
recruiting large sample sizes is needed in
future studies. Although 4 D sonography could be
useful in the study of fetal behavior, its
disadvantages cannot be overlooked.
Several movement patterns, such as bending
sideways, hiccup, and very subtle facial
movements, cannot be observed, especially early
in pregnancy . Moreover, as pointed out by
Kurjak and colleagues, only the quantity, and
not the quality, of facial movements can be
studied in fetuses, because criteria for quality
have not yet been determined . Presently,
studying fetal behavior is very time consuming
and therefore limited to research. An easier way
of analyzing fetal behavior should be developed
for diagnostic and prognostic use.
