Abstract : the emergence of
spontaneous fetal motility during the first 20
weeks of gestation was studied longitudinally in
11 healthy nulliparae, using real-time
ultrasound. The aim of this investigation was to
study the onset and developmental course of
spontaneously generated specific fetal movement
patterns. 60-min observations were repeated
weekly from 7 to 15 weeks and at 16/17 and 18/19
weeks. The qualitative aspects of fetal motility
and posture were analyzed during video
recording. Sixteen distinct movernent patterns
(just discernible movernents; startle; general
movements; hiccup; breathing; isolated arm or
leg movements; isolated retroflexion/rotation
and anteflexion of the head; jaw movements;
sucking and swallowing; hand-facecontact;
stretch; yawn; rotation), closely
resembling those observed in preterm and
fullterm newborn infants, could be distinguished
and a detailed description is presented. The
first movements were observed at 7.5 weeks
postmenstrual age. A scatter of two weeks was
found for the ages at which frequently occurring
movernent patterns could be observed for the
first time. By the age of 15 weeks all 16
movernent patterns could be observed. There
were no major changes between 8 and 20 weeks in
the appearance of the different movements, which
meant that they were easy to recognize at all
ages studied. A systematic assessment of
position and posture showed a preference for the
supine position before 16 weeks, and for the
lateral position after 16 weeks. There was no
consistent intra-individual preference for
position or posture. Two specific motor patterns
could be identified as causing either somersault
or rotation around the longitudinal axis. The
number of changes in fetal position increases
from 10 weeks onwards, reaches a peak at 13-15
weeks and decreases after 17 weeks
Results : As a result of the
observations made during the pilot study and the
eleven cases of the present investigation, we
arrived at the following classification of
sixteen distinct movement patterns.
Classification of movement patterns
Just discernible movements : Between
7 and 8.5 weeks postmenstrual age a slow and
small shifting of the fetal contours is seen
lasting from half a second to two seconds, which
usually occurs as a single event. The small size
of the fetus (about 2 cm) and the limited
resolution of contemporary scanning equipment
has so far impeded a more detailed analysis of
this type of movement.
Starfle : A startle is a quick
generalized movement, always initiated in the
limbs and sometimes spreading to neck and trunk.
Flexion or extension of the limbs is usually of
large amplitude, but can also be small or just
discernible. The movement lasts about one
second. Startles frequently occur as single
events but may sometimes follow each other in
rapid succession with a few seconds interval.
Startles can appear superimposed on a general
movement, or may be followed by a general
movement within ten seconds.
General movements : This category is
applicable if the whole body is moved but no
distinctive patterning or sequencing of the body
parts can be recognized. When they first appear
at 8 and 9 weeks, they are slow and of limited
amplitude. At 10-12 weeks general movements
become forceful. Movements of the limbs, trunk
and head are rapid but smooth in appearance. The
movements are of large amplitude and therefore
frequently cause a shift in fetal position
during this age period. After 12 weeks general
movements become more variable in speed and
amplitude. They may last from about 1 to 4 min
but wax and wane during this period. However
variable these movements are, they are always
graceful in character.
Hiccup : A hiccup consists of a jerky
contraction of the diaphragm. An abrupt
displacement of diaphragm, thorax and abdomen
can be seen on the scanning image. It lasts less
than 1 s. Hiccups frequently follow each other
in regular succession, but infrequently may
occur as single events. They are often followed
by passive limb and/or head movements. There is
a clear difference between startles and hiccups:
startles are initiated in the limbs, whereas a
hiccup begins wi th a jerky diaphragmatic
movement which may be followed by displacement
of the limbs.
Breathing : Fetal breathing movements
in utero are paradoxical in nature, i.e.
'inspirations' consisting of fluent simultaneous
movement of the diaphragm (caudal direction),
leading to movements of the thorax (inwards) and
abdomen (outwards). Each displacement of the
diaphragin lasts less than 1 s and can be either
small or large. Usually, breathing occurs
episodically and can be either regular or
irregular. The earliest breathing movements tend
to have a regular pattern. Although breathing
frequently occurs alone, it is sometimes seen in
combination with jaw opening and/or swallowing,
as well as with generai movements. A single
breathing movement with a large displacenient
of' the diaphragni mav reserrible a sigh.
Isolated arm or leg movement : These
may be rapid or slow movements, and may involve
extension. flexion. external and internal
rotation or abduction and adduction of an
extremity, without movements in other body
parts. The amplitude can vary from small to very
large. Extension of an arm is frequently
accompanied by extension of fingers at least
after 12 weeks. Slow arm movements often occur
unaccompanied by other movements. Slow leg
movements are rarely seen. Fast and jerky
movements of the arm or leg can occur either as
a single event (twitch) or as rhythmical
movements at a rate of about three to four per
second (clonus). The latter only occurs after 14
vveeks and is rare even then. Twitches and cloni
occur not only as isolated phenomena but inav
also be superimposed on general moverrients or
may precede them.
Isolated retroflexion of the head :
Retroflexions of the head are usually
carried out slowly, but can also be fast and
jerky. The displacement of the head can be small
or large. The latter may cause over-extension of
the spine of the fetus. The head may remain in
retroflexion for 1 s to more than 1 min.
Although most often seen as a single isolated
event, repetitive jerky retroflexion of the head
aiso occurs. Slow retroflexion of the head may
be accompanied by a wide opening of the jaws and
rotation of the head.
Isolated rotation of the head :
Rotation of the head is carried out at a slow
velocity and only exceptionally at a higher
speed. The head may turn from a midline position
to one side and back. The duration of the
movement is mostly longer than one second. The
movement frequently occurs as a single event,
but if repeated is never rhythmical. Rotation of
the head is often associated with
hand-face-contact.
Isolated anteflexion of the head :
Anteflexion of the head is only carried out at a
slow velocity. The displacement of the head is
small. The duration is about 1 s. Anteflexion
can occur alone and singly, but it also happens
rhythmically together with hand-face-contact,
when sucking can be observed.
Jaw movements : Jaw opening may be
either slow, or quick, The extent of jaw opening
is variable. The duration of opening varies from
less than 1 s to 5 s. The movement may occur
once or be repeated. Up to 15 weeks a single
wide opening of the jaws is more common than at
later age; irregularly repeated movements occur
more often after 15 weeks than before. Jaw
opening may occur alone or during general
movements, with hiccups (probably passive) and
with isolated head movements. Movements of the
tongue are also incidentally observed.
Sucking and swallowing : Rhythmical
bursts of regular jau opening, and closing at a
rate of about one per second may be followed by
swallowing, indicating that the fetus is
drinking amniotic fluid. Swallowing consists of
displacements of tonue and/or larynx.
Hand-face-contact : In this pattern
of movement the hand slowoly touches the face,
the fingers frequently extend and flex.
Insertion of fingers into the mouth can only
very rarely be seen accurately.
Hand-face-contact continues for a period of time
exceeding 1 s. It either occurs alone or as a
part of a general movement.
Stretch : A stretch is a complex
motor pattern, which is always carried out at a
slow speed and consists of the following
components: forceful extension of the back,
retroflexion of head, and external rotation and
elevation of the arms. This pattern always lasts
several seconds, and only occurs singly.
Yawn :
This movement is similar to the yawn observed
after birth: prolonged wide opening of the jaws
followed by quick closure often with
retroflexion of the head and sometimes elevation
of the arms. This movement pattern is
non-repetitive,
Rotation of the fetus : Rotation of
the fetus occurs around the sagittal or
transverse axis. A complete change in position
around the transverse axis, usually with a
backwards somersault, is achieved by a complex
general movement, including alternating leg
movements which resemble neonatal stepping.
Rotation around the longitudinal axis can either
be the result of leg movements with hip
rotation, or result from rotation of the head,
followed by trunk rotation. A total change in
fetal position can be achieved in as little as 2
s, but may take more time.
Developmental onset of specific fetal
movement patterns
The firstj ust discernible movements of the
fetus occur at 7 weeks and a few days in two out
of five observations, the rest follows at 8
weeks postmenstrual age. These movements are at
the limit of the resolution of our equipment.
After 9 weeks these kinds of movements are no
longer observed. All other previously mentioned
movement patterns, once observed, remain present
during the observation period until 20 weeks,
and many of thern can also be observed in
preterm and fullterm infants. Although eye
movements had been observed incidentally from 18
to 20 weeks, we did not pay special attention to
them, as they are difficult to observe without
special scanning procedure.
When the different movement patterns are
rank-ordered according to their first appearance
in the group of eleven fetuses, all fetuses
follow a specific sequence or developmental
profile. A certain scatter exists in the ages at
which each of the individual patterns are
observed for the first time over the group of
fetuses. This scatter is partly produced by the
1-week intervals between the observations
(resolution). The 2-weeks range found for
startles, general movements, hiccups, isolated
arm movements (more frequently occurring than
isolated leg movements) and breathing movements
may be also due to the scatter of conception in
relation to the first dav of the last menstrual
period. When we plotted the onset of patterns in
relation to crown-rump length, the ranges gave
an identical picture.
Another possible reason for the wide scatter
observed in some of the items (e.g., stretch,
head anteflexion, isolated leg movements and
sucking-swallowing) is their infrequent
occurrence. Thus, they may not be seen during a
particular hour of observation
