Sonographic diagnosis of
• First sonographic
evidence: 24 days
sac (5th week gestation
sac visualized within
the uterine corpus as
an echogenic ring with
a hypoechoic interior)
The sac is measured inside the
hyperechoic rim, including only the echo-
• The GS is imaged first in
the longitudinal plane,
obtaining long axis and AP
perpendicular to each
other. Then, in the
transverse plane at the
level of the anteroposterior
measurement, the width
measurement is obtained.
• Measurements are
averaged to obtain the GS
Development in the 1st trimester
• 6 to 8 weeks embryo appears as a
uniform echogenic structure within the
• 8th week: A head and trunk can be
identified. (Head/Trunk ratio : 50%)
• The physiological umbilical hernia may
be seen in few cases.
• 9th week: Evidence of limbs.
• 11th week: Increased differentiation of
the skull, trunk, limbs and of the organ
systems established during the
embryonic period, with progressive
ossification the skull is recognized as
consisting of a frontal bone, orbits,
maxilla and mandible.
• by the 12th week, the fetal spine
CROWN RUMP LENGTH(CRL)
• Accurate date
pregnancy between 7
and 13 weeks'
• Measurement of the
fetal length from the tip
of the cephalic pole to
the tip of the caudal
• The fetus should be at
rest and assuming its
Technical factors can lead to
errors in CRL measurements.
• Limbs in the CRL measurement,
• Excessive curling or extension of
• Tangential incorporation of the
yolk sac .
• Appears by the 6th or 7th
week as an echogenic sac
like structure located close to
the embryo within the
• Its diameter increases from 3
mm in the 7th week to 6 mm
in the 11th.
Corpus Luteum of Pregnancy:
• Can be seen in the early
pregnancy as a smooth
bordered hypoechoic cystic
mass next to the uterus.
• It usually disappears by the
3-4 weeks Implantation bleeding Perhaps some fluid in
Gestational sac not visible at
5-20 weeks Missed abortion Visible embryo. No embryonic
disorganization of gestational
sac and embryo
5-20 weeks Incomplete abortion Some retained products of
conception are nonspecific
10-20 weeks Early subchorionic
A fairly common occurrence.
Usually echo-poor crescentic
fluid collection beside
gestational sac. Embryo
5-20 weeks Other Ectopic pregnancy
Cervical lesions (not usually
detected with ultrasound)
Is the gestational sac normally located in the
endometrial cavity near the fundus•?
• A better term for blighted
ovum is anembryonic
gestation. The very early
embryo succumbs for
some reason (at 4-5
• Where the diagnosis is
not certain (the size of the
sac is at a borderline size
for identification of the
embryo), a repeat scan
should be performed in
approximately one week
• A spectrum of disorders that can develop in
• Hydatidiform mole is the most common
manifestation, representing 85% of cases.
Hydatidiform mole is noninvasive and remains
confined to the endometrium.
• Choriadenoma destruens is a locally invasive
(myometrium) manifestation that represents
13% of cases of GTD.
• Two percent of cases are described as
choriocarcinoma, which is locally invasive
(myometrium and parametrium).
Choriocarcinoma is also highly malignant,
spreading hematogenously to the lungs, brain,
liver, kidneys, bones, and GI tract
• The uterus may appear
enlarged and filled with a
hyperechoic mass with
many cystic structures.
• The cysts measure 1 - 2
mm. and may not be seen
sonographically. During the
2nd trimester, the cysts
enlarge to approximately 2
cm. in diameter
Suspected Ectopic gestation
• Specific feature: living embryo in adnexa .
• Non specific (correlate with b-HCG) :
Empty uterus .
Pseudo-gestational sac of ectopic pregnancy .
Particulate ascites .
Adnexal mass .
Ectopic tubal ring .
• In an ectopic pregnancy, the
fertilized egg may implant in:
– One of the fallopian tubes.
About 99% of ectopic
pregnancies occur in a
– One of the ovaries (very
– The cervix (very rare).
• The abdomen. This occurs in
just over 1% of ectopic
extremely rare, there are
reports of women developing
pregnancies after having a
• May arise from
Two separate ova
• Assessment of viability.
• Chorionicity and amnionicity.
(MZ)> depend on stage of division:
MC/DA > most common(70%).
MC/MA > incidence of conjoined
Chorionicity and amnionicity
Delta or lumda sign in
DCDA T sign in MCDA
• Transvaginal view of
an 8 week twin
• There is a normal
fetal pole in each sac,
and each sac has a
• Incidence of congenital anomalies appears
to be twice as common than in singleton
• Major malformation 2.1% in twins, 1.05%
in single fetus.
• Increased rate of anomalies in
monozygotic twins .
anatomy • The transventricular view is used
for measurement of the
biparietal diameter (BPD), head
circumference (HC), and width of
• The transcerebellar (or
suboccipitobregmatic) view allows
examination of the mid-brain and
posterior fossa; this view is used
for measurement of the
transverse cerebellar diameter
(TCD) and cisterna magna (CM).
• Measurement is obtained at the level of the
glomus of the choroid plexus, perpendicular to
the ventricular cavity with the calipers inside the
echoes generated by the lateral walls .
• The measurement is stable in the second and
early third trimesters, with a mean diameter of
6–8 mm and is considered normal when less
than 10 mm .. At mid gestation a value of 10.0
mm or greater should be considered suspicious
The depth of the cisterna
• measured between
the cerebellar vermis
and the internal side
of the occipital bone
is usually 2–10 mm
(Mahony, 1988). With
slightly larger than 10
mm may be
• Incidence :1/1000
• Errors of dorsal
• Failure of closure of
neural tube at cranial
• Absence of brain and
vault : frog like
• 1in 2000
• cranial defect with
varying degrees of
• most cases occurring
in the occipital and
• The mass may be
purely cystic, or it can
contain echoes from
• Holoprosencephaly is a complex abnormality of the
forebrain resulted from failure in the diverticulation of the
prosencephalon. It is classified in three major varieties:
• Alobar: single primitive ventricle; fused thalami; absence
of the third ventricle, neurohypophysis, olfatory bulbs
and the head is generally small;
• Semilobar: the two cerebral hemispheres are partially
• Lobar: the interhemispheric fissure is well developed
posteriorly and anteriorly, but there is still a variable
degree of fusion of the cyngulate gyrus and the lateral
ventricles and absence of the septum pellucidum.
• Chromosomal abnormality has been associated,
specially trisomy 13, but maternal infections and paternal
toxic exposures also can be implicated. All kinds of
holoprosencephaly can be diagnosed by ultrasound.
• Associated anomalies:
disgenesis of corpus callosum, cerebellar
hypoplasia, atresia of third ven-tricle,
midline proboscis, hypoplastic tongue,
tracheoesophageal fis-tula, cardiac
anomalies, and adrenal hypoplasia.
F, 24 y, 0000, negative consanguinity, no general
disease, discovered at 27weeks GA
• The most common diagnostic problem is
differentiation among :
• Schizencephaly .
• Extreme hydrocephalus.
• Alobar holoprosencephaly
• Some spared cortical mantle should still be
seen with porencephaly and alobar
• 1-2.5:10,000 births
• Absence of the cerebral hemispheres with an incomplete
or absent falx and a sac-like structure containing
cerebral spinal fluid surrounding the brainstem and basal
• Clefts in the cerebral
bilateral), lined by pia-
Choroid plexus cyst
• 0.4-3.6% , usually
isolated finding .
• Resolve by 22—26 GA.
• May be associated with
• Size 0.3– 2cm
• Unilateral bilateral
solitary or multiple
use of three-dimensional (3D)
• Evaluation of the fetal face is well established. The
advantages over standard 2D ultrasound include the
visualization of scanning planes that are physically
impossible or very difficult to obtain, the
demonstration of the surface of the face, and the
possibility of having panoramic views.
• The limitations of the technique are the same as for
2D sonograms. If the fetal face is not accessible or
there is not a pocket of amniotic fluid separating the
face from the surrounding structures, 3D willbe of
• Referred to as the Robin anomalad, which may be a
sporadic isolated finding (in about 40% of cases) or
may be associated with other anomalies or with
recognized genetic and non-genetic syndromes
including Treacher Collins, Robin and Robert
syndromes, Cornelia de Lange syndrome,
chromosomal abnormalities (mainly trisomy 18 and
triploidy) and teratogen exposure
• Suspected in the presence of
an abnormal skull shape
Failure to visualize the
sutures that are normally seen
as linear interruptions of the
increases the index of
• Recent reports on 3D
ultrasound suggest that this
technique may be valuable in
the diagnosis of
• Fetal yawning and
smiling as a marker of
fetal neurobehavior or
• The five axial views in the normal
• In the lower image the situs is
• The plane above is the 4-
chamber view (4CV).
• More cephalic is the left and right
• The highest plane is the arches
at the 3-vessel and trachea (3VT)
view. (From Yagel S, Cohen SM,
Achiron R. Obstet Gynecol
The following are features of body
• The typical ultrasound features are
• major abdominal wall defect.
• severe kyphoscoliosis.
• neural tube defect.
• limb abnormalities.
• malformed umbilical cord
• Absence of umbilicus and unbilical cord and
adherence of the placenta to the herniated
viscera through large anterior wall defect and
reduced amniotic fluid render foetus immobile
• Limb buds are first seen by ultrasound
at about the 8th week of gestation; the
femur and humerus are seen from 9
weeks, the tibia/fibula and radius/ulna
from 10 weeks and the digits of the
hands and the feet from 11 weeks.
• Body movements (wiggling) are seen
at 9 weeks and, by 11 weeks, limbs
move about readily.
• . At the 18–23-week scan, the three
segments of each extremity should be
visualized, but it is only necessary to
measure the length of one femur.
Malformation of fetal skeleton can
be classified into two major
Generalized type : multiple bones
are involved .
Focal type : a variable pattern both
in distribution and extent in
2. Asphyxiating thoracic
dysplasia (jeune syndrome).
3. Chondroectodermal dysplasia
(Ellis-van Creveld syndrome).
4. chondrodysplasia punctata.
5. Spondyloepiphyseal dysplasia.
6. Diastrophic dwarfism.
7. Metatrophic dwarfism.
Lethal Bone Dysplasia
(in order of frequency)
1. Thanatophoric dysplasia
2. Osteogenesis imperfecta,
3. Achondrogenesis type I + II.
Jeune syndrome (may be
dysplasia (usually nonlethal).
5. Chondrodysplasia punctata,
6. Camptomelic dysplasia.
7. Short rib
8. Homozygous achondroplasia.
• Routine conventional ultrasound is the main
prenatal screening method for skeletal
disorders, identifying abnormalities of fetal
bones (De Pellegrin et al., 2000).
• Detection of a shortended femur is the most
common indication that a skeletal dysplasia may
• Examination of all extremities will confirm
generalized involvement and help establish a
• The cranium and facies are evaluated
subjectively for facial dysmorphism. The limbs
are evaluated for rhizomelia, mesomelia and
acromelia, bowing and mineralization patterns.
Hands and feet are evaluated for relative size,
posturing and configuration of the phalanges.
The axial skeleton is inspected subjectively for
mineralization patterns, platyspondyly and rib
shape and length (Krakow et al., 2003).
Normal Sonographic Placental
• Sonographic pattern of the placenta changes
from a series of small white specules at around
8weeks gestation to a granular appearance by
10 weeks gestation.
• In the second trimester it becomes homogenous
with a non calcified texture.
• At about 20-24weeks, some echo free spaces
within the placental substance develop and
enlarge as pregnancy advances.
• After 36 weeks, the spaces becomes more
apparent and they are separated by wide
calcified areas of inter -cotyledons septa.
• US has become
indispensable in the
localization of the site of
the placenta and
determining its lower
edges, thus making a
diagnosis or an exclusion
of placenta previa.
• Other placental
conditions such as
diabetes, fetal hydrops,
Rh isoimmunization and
growth retardation can
also be assessed.
What is the position of the
• At about 7-8 weeks the
chorion frondosum begins
to thicken and form a
recognizable placenta. It
covers a large area in the
uterus at this stage. For
this reason it is best to
not try to diagnose
There are multiple variants, defined by the depth of
their attachment to uterine wall:
• Placenta accreta (75%) :An invasion of the
myometrium which does not penetrate the entire
thickness of the muscle.
• Placenta increta (17%) : Occurs when the
placenta further extends into the myometrium,
penetrating the muscle.
• Placenta percreta 5-7%: The worst form , the
placenta penetrates the entire myometrium to the
uterine serosa (invades through entire uterine
wall). This variant can lead to the placenta
attaching to other organs such as the rectum or
bladder[David Miller ,2004].
• The condition affects around 10% of cases of placenta
• Increased in incidence by the presence of scar tissue
i.e. Asherman's syndrome usually from past uterine
surgery, especially from a past Dilation and curettage,
(which is used for many indications including
miscarriage, termination, and postpartum hemorrhaging),
myomectomy, or caesarean section.
• A thin decidua can also be a contributing factor to such
trophoblastic invasion. Some studies suggest that the
rate of incidence is higher when the fetus is female.
PA is a clinical and diagnostic
• Ultrasonography (US) remains the
diagnostic standard, and routine US
examination at 18–20 weeks gestation
affords an ideal opportunity to screen for
the disorder. Placental lacunae and
abnormal color Doppler imaging patterns
are the most helpful US markers for PA
Normal placental interface
• a) Transverse transabdominal
US image shows the hyperechoic
placenta (*) surrounded by the
• (b) Sagittal transabdominal US
image shows a thin, hypoechoic
line (arrowheads) at the inner
aspect of the myometrium
representing a subplacental clear
• (c) Sagittal transabdominal US
image shows a normal organized
pattern of subplacental blood flow
that parallels the myometrium.
US Findings in PA
• Placenta previa
• Placental lacunae with turbulent flow
• Irregular bladder wall with extensive
• Loss of retroplacental clear space
• Myometrial thickness <1 mm or loss of
• of the myometrium
• Gap in the retroplacental blood flow
(a) Transverse transvaginal US image shows multiple
tortuous hypoechoic structures within the placenta.
(b) Transverse transabdominal Doppler US image helps
confirm that the hypoechoic spaces are vascular and
therefore represent placental lacunae.
Amniotic fluid index
– The volume of the amniotic fluid is
evaluated by visually dividing the
mother's abdomen into 4
quadrants. The largest vertical
pocket of fluid is measured in
centimeters. The total volume is
calculated by multiplying this value
– Polyhydramnios is usually defined
as an amniotic fluid index (AFI)
more than 24 cm or a single pocket
of fluid at least 8 cm in deep that
results in more than 2000 mL of
– Oligohydramnios is sonographically
defined as an AFI less than 7 cm or
the absence of a fluid pocket 2-3
cm in depth
• Excessive or decreased amount of liquor
(amniotic fluid) can be clearly depicted by
ultrasound. Both of these conditions can
have adverse effects on the fetus.
• In both these situations, careful
ultrasound examination should be made to
exclude intraulterine growth retardation
and congenital malformation in the fetus
such as intestinal atresia, hydrops fetalis
or renal dysplasia
• The normal colon is
visible in late pregnancy.
• Haustrations within the
colon can be seen from
about 30 weeks, and
peristalsis can be
• Large bowel obstruction
should be suspected if its
measures 20 mm or
Diagnosis of fetal malformation
• Many structural abnormalities in the fetus can be reliably
diagnosed by an ultrasound scan, and these can usually
be made before 20 weeks. Common examples include
hydrocephalus, anencephaly, myelomeningocoele,
achondroplasia and other dwarfism, spina bifida,
exomphalos, Gastroschisis, duodenal atresia and fetal
• With more recent equipment, conditions such as cleft
lips/ palate and congenital cardiac abnormalities are
more readily diagnosed and at an earlier gestational age.
• First trimester ultrasonic 'soft' markers for chromosomal
abnormalities such as the absence of fetal nasal bone,
an increased fetal nuchal translucency (the area at the
back of the neck) are now in common use to enable
detection of Down syndrome fetuses
• Biophysical profile (BPP)
– Described by Manning (1980)
– The number of biophysical activities that could
be recorded increased with real time
• Fetal movement (FM)
• Fetal tone (FT)
• Fetal breathing movements (FB)
• Amniotic fluid volume (AFV)
• Biophysical profile (BPP) – variables
– NST: reactive – as described earlier.
– FBM: present - at least 1 episode of at least 30
seconds duration (within a 30 minute period).
– FM: present - at least 3 discrete episodes.
– FT: normal - at least 1 episode of extension of
extremities or spine with return to flexion.
– AFV: normal – largest pocket of fluid greater than 1
cm in vertical diameter.
• Biophysical profile (BPP)
– Each variable
• When normal: 2
• When abnormal: 0
– Highest Score: 10, Lowest Score: 0
– Accuracy improved by increasing the number
of variables assessed.
– Overall false negative rate: 0.6/1000
• REACTIVE Repeat test weekly
• EQUIVOCAL :Stimulate movements with
motion, sound, or glucose drink
• SUSPICIOUS Repeat : test within 24 hours
• NON-REACTIVE : Consider other tests of
fetal wellbeing and consider
gestation re delivery
(Score = 2)
(Score = 0)
Fetal breathing movements 1 or more episodes of >20 s within
Absent or no episode of >20 s
within 30 min
Gross body movements 2 or more discrete body/ limb
movements within 30 min
(episodes of active continuous
movement considered as a single
<2 episodes of body/limb
movements within 30 min
Fetal tone 1 or more episodes of active
extension with return to flexion of
fetal limb(s) or trunk (opening and
closing of hand considered normal
Slow extension with return to partial
flexion, movement of limb in full
extension, absent fetal movement,
or partially open fetal hand
Reactive FHR 2 or more episodes of acceleration
of >15 bmp* and of >15 s
associated with fetal movement
within 20 min
1 or more episodes of acceleration
of fetal heart rate or acceleration of
<15 bmp within 20 min
Qualitative AFV 1 or more pockets of fluid
measuring >2 cm in vertical axis
Either no pockets or largest pocket
<2 cm in vertical axis
Fetal arterial Doppler
Umbilical arterial circulation
• The umbilical arterial circulation is normally a low
impedance circulation , with an increase in the amount
of end diastolic flow with advancing gestation .
• Umbilical arterial Doppler waveforms reflect the status
of the placental circulation, and the increase in end
diastolic flow that is seen with advancing gestation is a
direct result of an increase in the number of tertiary stem
villi that takes place with placental maturation.
• Diseases that obliterate small muscular arteries in
placental tertiary stem villi result in a progressive
decrease in end-diastolic flow in the umbilical arterial
Doppler waveforms until absent, and then reverse flow
during diastole is noted
:Normal umbilical cord
in long axis, the cord may be seen as a
series of parallel lines
short axis the arteries and
umbilical vein may be seen as
three separately circular lucencies
Color Doppler image will
demonstrate one color in vein
and another in the arteries
Umbilical Cord Abnormalities
Single umbilical artery( SUA): Absence of an
umbilical artery is believed to be present in
1% of all live births. This condition is frequently
referred to as a two vessel cord.
Primary agenesis of one of the arteries
Secondary atrophy of a previously present artery
Persistence of the original, single embryonic
Is associated with other fetal anomalies 25 -50% of the time. For
this reason,prenatal discovery of an absent umbilical artery
should prompt a thorough survey of the fetal anatomy.
Commonly associated abnormalities include:
Trisomies 13 and 18
VATER anomalies (Vertebral, Anal atresia, Tracheo-
esophageal fistula, Esophageal atresia, Radial aplasia, Renal
Absence of an umbilical
Two vessel cord
Care should be taken to
obtain a true transverse
section through the
When present, a
thorough examination of
fetal anatomy should be
Umbilical cord cysts
Omphalo-mesenteric duct cyst: A cystic
lesion of the umbilical cord due to the
persistence and dilatation of the embryonic
omphalo-mesenteric duct. The cysts are
generally located close to the fetus and vary
greatly in size.
Allantoic cyst: Cystic dilatation of the
primitive embryonic allantois.Usually small
and located within the cord away from the fetal
Umbilical cord cyst
Demonstration of an
umbilical cord cyst
Absence of blood flow
the two types is not
usually possible and is of
no clinical significance
• Doppler waveforms of the
umbilical arteries can be
obtained from any
segment along the
• Waveforms obtained
from the placental end of
the cord show more end
diastolic flow than
waveforms obtained from
the abdominal cord
The lower uterine segment
• Uterine dehiscence and rupture
• Pitfalls in assessing cervical length and
• Placental imaging in the lower uterine
segment : Placenta previa : Placenta
accreta, increta, and percreta
• Leiomyomas in the lower uterine segment
Ectopic pregnancy in the uterine scar