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 25-27weeks of gestation using 4D
ultrasound.
METHODS:
Twenty-four normal fetuses were examined
using 4D ultrasound. The face of each fetus was
recorded continuously for 15minutes. The
frequencies of tongue expulsion, yawning,
sucking, mouthing, blinking, scowling, and
smiling were assessed and compared with those
observed at 28-34weeks of gestation in a
previous study.
RESULTS:
Mouthing was the most common facial
expression at 25-27weeks of gestation; the
frequency of mouthing was significantly higher
than that of the other 6 facial expressions
(P<0.05). Yawning was significantly more
frequent than the other facial expressions,
apart from mouthing (P<0.05). The frequencies
of yawning, smiling, tongue expulsion,
sucking, and blinking differed significantly
between 25-27 and 28-34weeks (P<0.05).
CONCLUSION:
The results indicate that facial expressions
can be used as an indicator of normal fetal
neurologic development from the second to the
third trimester. 4D ultrasound may be a valuable
tool for assessing fetal neurobehavioral
development during gestation.
1. Introduction
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.
