Download OBSTETRICS. A Whole Lot of Nothing or A little Bit of Not Much

OBSTETRICS
A little bit of everything or,
a whole lot of not much
Holdorf
Second and Third Trimester
Placenta
Placenta Development
 The
placenta is a
mateno-fetal
organ which
begins
developing at
implantation of
the blastocyst
and is delivered
with the fetus at
birth.
This is a normal fetal ultrasound performed at
17 weeks gestation. In the foreground to the
left and middle of the screen, you can see the
placenta, following the curve of the uterus.
Placental Positions

Placental development may
occur on any side of the
gestational sac:

Anterior

Posterior

Lateral (right/left)

Fundal
Fundal
Posterior
Umbilical Cord

The umbilical cord is the lifeline that attaches the
placenta to the fetus. The
umbilical cord is made up of
three blood vessels: two
smaller arteries which carry
blood to the placenta and a
larger vein which returns
blood to the fetus. It can
grow to be 60 cm long,
allowing the baby enough
cord to safely move around
without causing damage to
the cord or the placenta.
Placenta Abruption

When the uterus bleeds from the site where the placenta was
attached. The blood typically passes through the cervix and
out the vagina. Sometimes, however, the blood remains
trapped behind the placenta. Left untreated, placental
abruption puts both mother and baby in jeopardy.
Placenta Previa
 The
implantation of the placenta at least
partially covering the cervix.
 There are actually three types of previa.
Complete previa where the cervical os is
completely covered. Partial previa where
just a portion of the cervix is covered by
the placenta. And the marginal previa that
extends just to the edge of the cervix.
Partial Placenta Previa
The placenta partially covers the internal os.
Marginal Previa
Transvaginal sagittal view which shows a posterior marginal placenta
previa extending about 2 cm over the internal os.
Complete Previa
Maturity/Grading
Placental Grading Based on Placental Calcification
1. Placental Grading
Grade 0 No calcifications (to about 31 wk)
I Scattered calcifications (31 – 36 wk)
II Basal Calcifications (36 – 38 wk)
III Basal and interlobar septal calcifications (38 wk to
term)
2. The placenta matures considerably after the 40th week.
3. Two parts of the placenta may have different grades, in
which the highest grade is assigned.
4. Most term pregnancies have grade I or II placentas.
5. Only about 10% - 15% of term placentas are grade III.
Grade 0
Late 1st trimester-early 2nd trimester
Uniform moderate echogenicity
Smooth chorionic plate without indentations
Grade 1
Mid 2nd trimester –early 3rd trimester (~18-29 wks)
Subtle indentations of chorionic plate
Small, diffuse calcifications (hyperechoic) randomly dispersed in placenta
Grade 2
Late 3rd trimester (~30 wks to delivery)
Larger indentations along chorionic plate
Larger calcifications in a “dot-dash” configuration along the basilar plate
Grade 3
39 wks – post dates
More irregular calcifications with significant shadowing
Placenta Accreta
 Placenta
accreta is a severe obstetric
complication involving an abnormal
attachment of the placenta to the
myometrium.
 There are three forms of placenta accreta,
distinguishable by the depth of
penetration.
Placenta Accreta

The most common form of placenta accreta
which is the invasion of the myometrium
which does not penetrate the entire
thickness of the muscle.

Placenta increta occurs when the placenta
extends into the muscle of the uterine wall.

Placenta percreta, the worst form of the
condition is when the placenta penetrates
the entire uterine wall.
Placenta Accreta
Typical image of massive
anterior placenta percreta. US
Doppler shows the newly
formed vessel between uterus
and the bladder.
Multiple Gestations
Diamniotic

Diamniotic pregnancy is when there are
more than one amniotic sac.
Monoamniotic

Monoamniotic twins are
identical twins who share
the same amniotic sac.
This very rare condition
occurs in an estimated 1
in 25,000 to 1 in 60,000
pregnancies, and
historically has resulted in
the in-utero death of one
or both babies in 50 to 70
percent of cases.
Complications of the Fetus and
Newborn with Multiple Gestation

Preterm births.

Compared to singleton pregnancies, a twin is seven times more
likely and a triplet is over 20 times more likely to die in the first
month of life.

Prematurity is associated with an increased risk of respiratory
distress syndrome (RDS), intra-cranial hemorrhage, cerebral
palsy, blindness, low birth weight, and neonatal morbidity and
mortality.

Intrauterine growth restriction, intrauterine death of one or
more fetuses, miscarriage, and congenital anomalies are all
more common.

Lifelong disability is over 25% for babies weighing less than
1,000 grams.
Maternal Complications Associated with
Multiple Gestation

Preeclampsia, also called pregnancy-induced
hypertension, occurs three to five times more frequently.

Premature labor requiring prolonged bed rest or
hospitalization is common.

Placental abnormalities associated with maternal
hemorrhage are more likely to occur.

Gestational diabetes, anemia, and polyhydramnios occur
more frequently.

Cesarean section is often needed for twin pregnancies
and almost always required for triplets.
Fetal Abnormalities
Cranial Abnormalities
Hydrocephaly

Dilatation of ventricular
system secondary to an
increase in the amount of
CSF. Effects include
flattening of parenchyma,
intraparenchymal
effusions which cause
demyelination and brain
damage.
Cranial Abnormalities
Hydranencephaly

Total or near total
absence of
cerebral
hemispheres with
normally
developed
meninges and
skull. Cerebellum
and midbrain,
including basal
ganglia are intact.
14 weeks shows unfused thalami surrounded
by fluid in this fetus with hydranencephaly.
Note the lack of cerebral hemispheric tissue.
Cranial Abnormalities
Holoprosencephaly

Abnormality of forebrain
diverticulation leading to a
single large midline
ventricle. Spectrum of
pathologic findings include:

Alobar: (most severe)
large single cavity with
minimal amount of
cerebral tissue
surrounding it, fused
thalami, and a facial
syndrome.

Semilobar: more cerebral
tissue present, occipital
lobe present.
Cranial Abnormalities
Porencephaly

The presence of
cystic areas
within the
cerebral
parenchyma.
Cranial Abnormalities
Dandy-Walker Syndrome
 Characterized



by:
Posterior Fossa
Cyst continuous
with 4th vent.
Posterior fossa
enlargement.
Cerebellar vermian
dysgenesis.
Cranial Abnormalities
Choroid Plexus Cysts
 The
presence
of simple cysts
within the
choroid plexus.
Cranial Abnormalities
Microcephaly

Small head greater
than 3 standard
deviations below
normal.
Cranial Abnormalities
Agenesis of Corpus Callosum

Absence of the
corpus callosum
resulting from a
chromosomal
abnormality or a
chromosomal
translocation. May be
complete or partial.
Cranial Abnormalities
Intracranial Tumors
 Rare
occurrence.
May be cystic,
solid, or complex.
Facial Abnormalities
Facial Clefts
Failure
of lip fusion, normally complete by
35 days of intrauterine life.
Bilateral Cleft Lip
Facial Abnormalities
Epignathus

A teratoma arising
from the oral cavity or
pharynx. May arise
from the sphenoid
bone, hard or soft
palate, pharynx,
tongue or jaw.
Neck Abnormalities
Cervical Teratoma
 Similar
to
epignathus
expect the tumor
arises from the
neck.
Neck Abnormalities
Nuchal Thickening
 Increased
soft
tissue thickness
over the
posterior aspect
of the neck.
Neck Abnormalities
Cystic Hygroma

Benign
developmental
anomaly of lymphatic
origin characterized
by single or multiple
cystic areas within
soft tissues
surrounding the neck.
Neural Tube Abnormalities
Anencephaly

Anencephaly, a
congenital anomaly in
which the cerebral
hemispheres and
overlying skull and
scalp are entirely
absent, is the most
obvious and dramatic
of the “absence”
abnormalities..
Note the absence of cranial tissue.
Neural Tube Abnormalities
Cephalocele/Encephaloceles

Protrusions of the
meninges and frequently of
brain substance through a
defect in the cranium.
Encephaloceles contain
brain tissue and cranial
meningoceles do not.
Although cephalocele
usually result from a defect
in neural tube closure, they
may be seen in the amniotic
band syndrome or in
association with various
malformation syndromes.
Neural Tube Abnormalities
Spina Bifida and Meningomyelocele

Spina bifida refers to a
defect in the spine
resulting from a failure of
the two halves of the
vertebral arch to fuse.
These lesions usually
occur in the lumbosacral
and cervical regions. If
the meninges protrude
through the defect, the
lesion is designated a
meningocele; if neural
tissue is included, it is a
meningomyelocele.
No fusions
Abdominal Wall Abnormalities
Omphalocele

Herniation of abdominal
viscera into the base of
the umbilical cord. May
be caused by failure of
fusion of the lateral
ectomesodermal folds or
by persistence of the
body stalk in the area
normally occupied by the
abdominal wall.
Abdominal Wall Abnormalities
Gastroschisis

Smaller herniation of
abdominal viscera
through an off-midline
defect in the
abdominal wall,
usually located just to
the right of the
umbilicus.
Abdominal Wall Abnormalities
Umbilical Cord Hernia

Protrusion of a small
amount of intestine at
the umbilicus.
Abdominal Wall Abnormalities
Bladder Extrophy

Congenital failure of
abdominal wall to
develop over bladder;
urinary bladder may
protrude thorough
abdominal wall.
A 35 week male fetus with bladder
extrophy.
Genitourinary Abnormalities
Ureteropelvic Junction Obstruction

Narrowing (stricture) at
this junction which
reduces the flow of urine
from the kidney and can
result in enlargement of
the kidney caused by the
backup of urine into the
renal pelvis
(hydronephrosis) and
kidney damage. UPJ
obstruction can be
severe, minimal, or
intermittent.
Postnatal ultrasound confirmed the
ureteropelvic junction obstruction.
Genitourinary Abnormalities
Ureterovesical Junction Obstruction

Rare, and is noted by
dilatation of the ureter
to the level of the
bladder.
Genitourinary Abnormalities
Bladder Outlet Obstruction

Bladder outlet
obstruction occurs at
the base of the
bladder, and reduces
or prevents the flow of
urine into the urethra.
Keyhole Appearance
Genitourinary Abnormalities
Posterior Urethral Valves

Predominantly a male
abnormality because
of redundant
membranous folds in
the posterior urethra
that lead to varying
degrees of GU
system obstruction.
Axial ultrasound image depicts a
massively distended bladder with a
keyhole appearance posteriorly.
Gastrointestinal Abnormalities
Esophageal Atresia

Esophageal Atresia is
a disorder of the
digestive system in
which the esophagus
does not develop
properly. The disorder
is a congenital defect,
which means it occurs
before birth.
Gastrointestinal Abnormalities
Midgut Volvulus

Midgut volvulus refers
to twisting of the
entire midgut about
the axis of the
superior mesenteric
artery.
Gastrointestinal Abnormalities
Duodenal Atresia

Duodenal atresia is
due to the failure of
canalization of the
embryonic
duodenum.
35 week fetus demonstrating the "double
bubble" sign characteristic of duodenal
atresia.
Skeletal Abnormalities
Achondrogenesis

A rare, lethal form of short-limbed
dysplasia. It is the failure of
ossification process. Two Types:

Type I (Parenti-Fraccaro)
• Absent vertebral ossification
centers
• Incomplete ossification of skull
• Rib fractures
• Arms extremely short and
stubby
• Head not enlarged compared to
trunk

Note the
absent
ossification
of
the skull.
Type II (Langer-Saldino)
• Head large compared to body
• Prominent skin folds over a
short neck
• Small chest
• Distended abdomen and
possible fetal hydrops
• Very short limbs held away
from body
Short arm
does not
reach the
anterior
midline.
Skeletal Abnormalities
Homozygous Dominant
Achondroplasia

A lethal, short limbed
dysplasia
characterized by
rhizomelic dwarfism,
limb bowling, lordotic
spine and a bulky
head. It occurs in
fetuses in which both
parents are
achondroplastic
dwarfs.
Cloverleaf Skull
Skeletal Abnormalities
Thanatophoric Dysplasia

Lethal skeletal dysplasia
characterized by extreme
rhizomelia (shortening of
the proximal segment of
an extremity), bowed long
bones, narrow thorax with
normal trunk length, a
relatively large head, and
severely flattened
vertebral bodies. Thorax
is narrow and respiratory
distress usually follows
birth leading to death.
Fig. 1. Thanatophoric dysplasia in a 21-week fetus.
A. Demonstrates a cloverleaf-like skull.
B. Rhizomelic micromelia with bowing of the humerus is apparent
(arrows). The skin appears thick because of extreme redundancy
Skeletal Abnormalities
Campomelic Dysplasia
 A skeletal
dysplasia
characterized by
bent or bowed
limbs.
Femoral bone deformity.
Skeletal Abnormalities
Short-Rib Polydactyly Syndrome

A lethal dysplasia
characterized by
polydactyly and an
extremely narrowed
thorax.
Fig. 5. Short-rib dysplasia with polydactyly in a
21-week fetus.
A. Sagittal image shows a narrow thorax and
relatively protuberant abdomen (arrows).
B. There is an extra digit (6) lateral to the fifth
finger.
C, D. Autopsy photographs show a narrow
thorax with short ribs, a protuberant abdomen,
micromelia, and postaxial polydactyly (arrow).
Skeletal Abnormalities
Osteogenesis Imperfecta

Disorder production,
secretion or function
of collagen. Abnormal
fragility of bone
caused by
hypomineralization.
Axial scan of fetal head,
demonstrating poor
ossification of the skull and
easy compression of the
calvarium.
Skeletal Abnormalities
Hypophosphatasia

A bony
demineralization
disorder resulting
from low levels of
serum and tissue
alkaline phosphate.
Skeletal Abnormalities
Talipes Equinovarus (Club Foot)

Inversion of the foot
and flexion of the
sole.
Skeletal Abnormalities
Sirenomelia (Mermaid Syndrome)

Lower extremity
fusion which is a
severe manifestation
of caudal regression
syndrome.
Cardiac Abnormalities
Atrial Septal Defect
and
Ventricular Septal Defects

ASD - Any abnormal
opening between the
atria.

VSD - Caused by
incomplete closure of
interventricular foramen
and failure of the
membranous part of IV
septum.
Ventricular and Atrial Septal Defects. This is a hole in the wall
that separates the two ventricular and atrial chambers. This is
also known as an endocardial cushion defect or an AV canal
defect. When this is present the risk for Down syndrome is 50%.
Cardiac Abnormalities
Transposition of the Great Arteries

The origin of
the great
vessels are
transposed
so that the
aorta arises
from right
ventricle and
pulmonary
trunk arises
from the left
ventricle.
Cardiac Abnormalities
Ectopic Cordis

All or part of heart
is located outside
of chest cavity.
Transverse scan demonstrating ectopic 4
chamber view of the heart (right)
Coexisting Disorders
Leiomyoma

Leiomyomas or
uterine fibroids are
benign tumors of the
uterus. Leiomyomas
arise from the
overgrowth of smooth
muscle and
connective tissue in
the uterus.
The uterus appears enlarged and
shows the presence of a large
hypoechoic mass in the region of
the lower uterine body and uterine
cervix.
Gestational Trophoblastic Disease

A designation given to
several disorders arising
from either normal or
abnormal fertilization of
an ovum, resulting in
neoplastic changes in the
trophoblastic elements of
the developing
blastocysts. GTD is
classified into hydatidform
mole, nonmetastatic
disease or invasive mole;
and metastatic disease or
choriocarcinoma.
Hydatidform Mole
Myometrial Contraction

Throughout the
pregnancy, focal
areas of smooth
muscle in the uterine
wall contract, causing
a bulging into the
amniotic cavity.
Placenta appears to become thicker
due to a focal myometrial contraction.