Piontelli
A. Fetal Yawning in Development of
Normal Fetal Movements. The fisrt 25 weeks of
gestation. Spinger. 2010.
135p.
OBJECTIVE:
To assess the frequency of fetal facial
expressions at 20-24weeks of gestation using
four-dimensional (4D) ultrasonography and to
determine whether there was any correlation
between facial expression and gestational age
(20-34weeks).
METHODS:
The facial expressions of 23 healthy fetuses
were examined using 4D ultrasound at 20-24weeks.
Each fetus was recorded continuously for
15minutes. The frequencies of mouthing, yawning,
smiling, tongue expulsion, scowling, sucking,
and blinking were assessed and the data combined
with those expressions observed at 25-34weeks of
gestation in two previous studies (n=34) to
determine the correlation between gestational
age and each of the facial expressions.
RESULTS:
Mouthing was significantly more frequent
than the other six facial expressions at
20-24weeks (P<0.05). Yawning was
significantly more frequent than smiling,
scowling, and blinking (P<0.05), and sucking
was significantly more frequent than smiling,
scowling, and blinking (P<0.05). The
frequency of yawning, smiling, tongue expulsion,
scowling, and blinking increased with
gestational age (P<0.05). Mouthing movement
and sucking frequencies remained constant
between 20 and 34weeks.
CONCLUSION:
Frequencies of complicated facial
expressions such as smiling and scowling may
increase with advancing gestation owing to the
development of the fetal brain and central
nervous system.
Fetal facial expressions are thought to be
indicative of normal fetal neurologic
development. In a previous study in which 4D
ultrasound was used to assess fetal facial
expressions, it was shown that fetuses display a
broad spectrum of facial expressions&emdash;as
seen during emotional expression by adults;
thus, it might be possible to use 4D ultrasound
to assess fetal condition. Assessing facial
activity using conventional 2D ultrasound is
hard because of the complexity of facial anatomy
and the limited utility of conventional 2D
ultrasound. In a previous investigation, fetal
facial expressions were examined at 28&endash;34
weeks of gestation using 4D ultrasound. Mouthing
was significantly more common than all of the
other facial expressions, and scowling and
sucking were the rarest expressions. The aim of
the present study was to evaluate the
frequencies of fetal facial expressions at
25&endash;27 weeks of gestation using 4D
ultrasound in order to assess fetal neurologic
developmental levels during gestation.
4. Discussion
Several studies have involved 4D ultrasound
examinations of fetal facial expressions late in
the second trimester and early in the third
trimester. Kurjak et al. detected variations in
facial expression frequency in the second and
third trimesters. The frequencies of all of the
examined facial expressions peaked during the
latter stages of the second trimester, except
for that of isolated eye blinking, which
increased at the start of week 24. During the
early stages of the third trimester, decreased
or unchanged fetal facial expression frequencies
were observed. In the study by Yigiter and
Kavak, the frequencies of yawning, sucking,
swallowing, smiling, mouthing, and tongue
expulsion were highest at 24&endash;32 weeks,
whereas grimacing peaked at 28&endash;36 weeks
and eye blinking peaked after week 32. Kurjak et
al. also reported that concurrent eyelid and
mouthing movements were the predominant
expressions at 30&endash;33 weeks.
In the present and previous investigations,
the most frequent facial expression was mouthing
at 25&endash;27 and 28&endash;34 weeks of
gestation; the frequency was significantly
higher than that of the other facial
expressions. The frequency of yawning was
significantly higher than that of the other
facial expressions, except for mouthing, at
25&endash;27 weeks. Moreover, the frequencies of
yawning, smiling, tongue expulsion, sucking, and
blinking at 28&endash;34 weeks were
significantly higher than those observed at
25&endash;27 weeks. The reasons for the
discrepancies between these findings and those
of other groups regarding the incidences of
fetal expressions during the latter stages of
the second trimester and the early stages of the
third trimester are unknown. However, 4D
ultrasound assessments of fetal facial
expressions rely on the subjective judgment of
the examiner, so inter-observer variabilitymight
be an issue with 4D ultrasound assessments of
fetal facial expressions. Further studies are
needed to determine appropriate levels of
inter-observer agreement for such
investigations. Moreover, an objective method of
analyzing facial expressions using automated
objective recognition systems should be
developed. The frame rate of the machine
employed in the present study might also have
affected the results. In previous studies, the
frame rate was 0.5 frames per second, except for
1 study in which it was 4&endash;6 frames per
second; by contrast, the maximum frame rate in
the present study was 40 frames per second.
Other possible reasons for the discrepancies are
the small study populations examined in the
present study and those of previous researchers,
and variations in examination time among the
studies. Examinations in the present study
lasted 15 minutes, as was the case in other
studies, whereas they took 30 minutes in 2 other
investigations. The problems associated with a
short examination period have been described by
Kurjak et al. More studies involving larger
study populations and an extended observation
period are required to assess precisely the
frequencies of fetal facial expressions during
the second and third trimesters of
pregnancy.
As stated by Kurjak et al., the ability to
evaluate fetal behavior might increase knowledge
regarding fetal central nervous system
development. In addition, it might be possible
in future to use the functional characteristics
of a fetus, as determined by 4D ultrasound, to
predict potential developmental problems. 4D
ultrasound examinations of fetal facial
expressions might provide useful information for
diagnosing and understanding fetal brain
disorders in utero, and they could even result
in the elucidation of novel fetal behavioral
functions. Kurjak et al. developed a
points-based system (the Kurjak Antenatal
Neurological Test) for evaluating the neurologic
status of fetuses via 4D ultrasound, and several
studies have assessed the utility of 4D
ultrasound for distinguishing between normal and
borderline or abnormal fetal behavior during
both normal and high-risk pregnancies. The
present study offers new insights into the
neurologic development of the fetus and might
help to determine whether frequencies of fetal
facial expressions at a specific gestational age
are indicative of specific neurologic disorders.
Further studies are necessary to clarify the
potential of 4D ultrasound for evaluating fetal
neurobehavior.
