Pocket Atlas of Obstetric Ultrasound: OB 1 Flashcards

Complete Breech

Frank Breech

Footling Breech

6-12 weeks

0 - 13 weeks

12 + weeks

14 - 26 weeks

in a marginal abruption the hemorrhage dissects beneath the placental
membrane & is associated with little detachment
in a retro-placental abruption if the blood remains
retro-placental the patient has no visible bleeding

280 days

patient habitus

to measure the cervix
The bladder needs to be full to measure the
cervix, after that a full bladder is not required

3 cm

BPD
HC
AC
Femur Length
HC/AC
CI
CIterna Magna
Ventricular Atria
Amniotic fluid (AFI)
Cerebellum

Face
Neck & Spine
4 chamber heart
diaphragm
stomach
kidneys
bladder
cord - 3 vessels
cord insertion
extremities
placenta
fetal lie
genitalia

generic term for head down

longitudinal lie
transverse lie
oblique lie

Left Occiput Posterior
LOP

Left Occiput Transverse
LOT

Left Occiput Anterior
LOA

Right Occiput Posterior
ROP

Right Occiput Anterior
ROA

Right Occiput Transverse
ROT

single footling
double footling

external cephalic version

OR must be booked in case of an emergency birth.

Shoulder Dystocia

obstructed labour whereby after the delivery of the head, the
anterior shoulder of the infant cannot pass below, or requires
significant manipulation to pass below, the pubic symphysis. It is
diagnosed when the shoulders fail to deliver shortly after the fetal head.

anterior and posterior fontanel presenting

90%

3% to 4%

6.3%

2.4%

transverse

slide inferior

drinking water (filling bladder)
trendelenburg

Faux cerebri (IHF)
Choroid Plexus
cavum septum pellucidum
Thalami
Cerebral peduncles
cerbellum & cisterna magna
Nuchal fold
orbits
profile
coronal facial views

separation of the cerebrum has occured

Faux cerebri

produce cerebrospinal fluid

Choroid Plexus

10 mm or less

to exclude ventricular megaly

ventricular megaly

dangling choroid plexus

none baby can become brain surgeon or
increase the risk of T18

Trisomy 18, also known as Edwards syndrome, is a condition which is
caused by an error in cell division, known as meiotic disjunction. When
this happens, instead of the normal pair, an extra chromosome 18
results (a triple) in the developing baby and disrupts the normal
pattern of development in significant ways that can be
life-threatening, even before birth. A Trisomy 18 error occurs in
about 1 out of every 2500 pregnancies in the United States, about in
about 1 in 6000 live births. The numbers of total births is much
higher because it includes significant numbers of stillbirths that
occur in the 2nd and 3rd trimesters of pregnancy.

Cavum Septum Pellucidum

arched band of nervous tissue that connects left & right cerebrum

excludes agenesis of corpus callosum

the level of the thalami

receive sensory impulses and transmits them to the cerebrum

thalami view

receive impulses from brain stem and transmit them to cerebrum
2-way path

first find the thalami and the peduncles with pop out

cerebral peduncles

equilibrium

10 mm or less

skin behind the neck

5 mm of less

rules out trisomy 21
production of abnormal amounts of collagen
Down-syndrome

No eyes

close eyes

far eyes

to rule out
hypotelorism
hypertelorism
anophthalmia

orbits

exclude
anterior cephalocele - unicorn bony defect
frontal bossing

unicorn bony defect

protuding forehead

Bad news -
aniplody
downs syndrome
tripody 21
Beckwith-Wiedemann syndrome

an overgrowth syndrome, which means that affected infants are
considerably larger than normal (macrosomia) and tend to be taller
than their peers during childhood.

no chin

exclude cleft lip
evaluate the integrity of nasal

7

widens

12

5

5

4

tapers

follow skin covering
2 orientations

isoechoic to the liver

hyperechoic to the liver

positioning

Rescan at 14 to 15 weeks to rule out rotation of mid gut

apex of heart points to left
stomach - left
liver right
GB on right

65%

85%

18 weeks gestation

...

shunting of blood from right to left

60%

eustation valve

exclude wall defects

baby lieing on back

angle up from 4 chamber view

angle up from aorta

heart superior to diaphragm
stomach inferior to diaphragm

left side

stomach can move to the thoracic

no stomach
esophagus ends in bind end tube

11 wks

16 wks

rule out meconium spillage
cystic fibrosis

to rule out anal atresia

dilated loops of bowel

15 weeks

retroperitoneal

1/3

5 mm or less

7 mm or less

BAD

superior to the kidneys

20 weeks

can mimic kidneys
especially when kidneys are missing

50% the size of the kidneys

8 - 11 weeks

at least one kidney exists

16 weeks

produce amniotic fluid

30 to 45 minutes

34 weeks

20 weeks
possible at 14 weeks

hemophilia

20 weeks
possible at 14 weeks

determine fetal age
detection of skeletal dysplasia
detection of limb malformation

dwarfism

39 weeks

gestational age between 33 - 35 weeks

3 bones visible

open good
closed fist - BAD BAD BAD

downs syndrome

gap between big toe and 2nd toe

movement
temperature control
shock absorber
normal lung development

amniotic fluid index?

kidneys, lungs, cord & skin

20 weeks

anechoic
floating vernix caseosa

after 24 weeks

too little fluid

...

bad lung formation

pulmonary hyperplasia
joint defect from restriction

evaluation of fetal well being

NST
fetal tone
fetal breathing
fetal movement

Neonatal stress test
presence of 2 or more fetal heart rate
accelerations of at least 15 bpm in amplitude & of at least 15
seconds in duration associated with fetal movement in a 20 minute period

extension & flexion

30 seconds worth

trunk movement

2 cm puddle

fetal age
restricted to pregnancies in which the actual
date of conception is known
- in vitro fertilization
- artificial insemination

menstrual age

used my
LMP - 3 months + 7 days

gestational age

first day of LMP

scedule invasive procedures
alpha-feto-protein screening
plan date of delivery
evaluate fetal growth

3 CRL
Crown rump length

+/- 5 days
95%

pathological conditions minimally affect growth in the first trimester

(CRL)cm +6

after 12 weeks

due to movement including extension and flexion

Biparietal diameter

+/- 11 days

+/- 3 weeks

outer to inner

Falx cerebri
cavum septum pellucidum
thalami

13 - 14 weeks

fetus is too big for CRL yet the landmarks for a BPD are not seen yet.
Use choroid plexus and head shape as the landmark

(BPD + OFD)(Pie)/2

outer to outer

less affected by head compression

ovid

a round head

overestimate

elongated head

underestimate

devised to determine the normality of the fetal head shape

BPD / OFD x 100

dolichocephaly

brachycephaly

Normal

abdominal circumference

level of the liver where the umbilical vein branches in the left
portal vein

transverse

(D1 +D2)(pie) /2

stomach
3 ossification centers of the spine
portal vein

Useful in predicting fetal weight
useful in monitoring normal fetal growth
AC size is a direct indicator of the size of the liver
useful in detecting fetal growth disturbances
such as IUGR

about as accurate as BPD

fetal head can not be measured due to position or anomaly
fetal death

from greater trochanter to the distal femoral condyle

measure all fetal bone
targeted exam should be done to rule out pathology
trisomy
dwarfism

trisomy
dwarfism

ocular distance (OD)
binocular distance (BD)
interocular distance (IOD)

between eyes

distance from outer orbit to contra-lateral outer orbit

distance of the orbit

BD binocular distance

outer to outer

when ventriculomegaly or skeletal dysplasia exists making BPD
measurements inaccurate.

Hypotelorism
hypertelorism
anophthalmus
microphthalmos

close eyes

wide eyes

no eyes

small eyes

vermis and 2 lobes

good correlation with GA
excluding Arnold Chiari seen in spina bifida
Dandy Walker syndrome

downward displacement of the cerebellum through the foramen magnum
banana shaped cerebellum

hypoplasia of the vermis and cephalad rotation of the vermian
remnant cystic dilatation of the fourth ventricle extending
posteriorly

tissue from both mother and fetus

Chorionic plate
chorion frondosum

Decidua basalis
endometrial surface

uterine lining (endometrium) during a pregnancy, which forms the
maternal part of the placenta.

influence of hormones

1

6

5

11

12

13

functioning unit of the placenta
finger-like structures containing one fetal blood
capillary per villi

intervillious space

exchange of:
nutrients
waste
oxygen
carbon dioxide

low

uterine arteries
intervillous spaces
villous capillaries
umbilical vein
umbilical artery
villous capillaries
intervillous space
basilar vein

Nutrition
respiration
excretion
protection
storage
hormone production (chorionic villi)

position
echotexture / grade
size

grading

...

Rh disease
diabetes

smooth edges
homogeneous
1st - early 2nd

small intraplacental calcifications
as early as 14 weeks
common until 34 weeks

calcifications at basilar plate
greater than 30 weeks

calcified indentions of placenta
35 weeks +
1/3 of term placenta

maternal diabetes
Rh sensitivity

maternal HTN
IUGR
smoking

placental infarct
primary placental growth retardation
interuterine infection
chromosomal anomalies

maternal diabetes
maternal anemia
non-immune Hydrops
interuterine infection
chromosomal anomalies

less than 4 cm
1 mm thick for every week gestation

attaches to myometrium

invades myometrium

penetrates through uterus
(myometrium and serosa)

placental previa
Hx of C-section
uterine surgeries
advanced maternal age

elevated maternal serum AFT
MRI
Sonography

absent or thin myometrium under placenta
multiple lakes
increased vascularity
(Percreta) extrauterine mass
swiss cheese

...

miscarriage

Fetal Death

premature separation of the implanted placenta between 20 weeks and birth

preterm labor / delivery
fetal death

history
physical findings:
-back pain
-bleeding

vaginal bleeding
pelvic pain
shock
asymptomatic

hx of abruption
trauma
fibroids
placental previa

rupture of the spiral artery
separation of basal plate from the uterine wall
high pressure bleeds

HTN
vascular disease

anechoic subchorionic area between placenta and uterus
thickened uterus
collection greater than 2 cm

tears in the marginal vein
separates the chorion from decidua
low pressure bleed

maternal cig smoking

anechoic subchorionic area between placenta and uterus

in a marginal abruption the hemorrhage dissects beneath the placental
membrane & is associated with little detachment
in a retro-placental abruption if the blood remains
retro-placental the patient has not visible bleeding

less than 5 cm

less than 2.5

placental previa

multigravida
hx of c-sec
hx of therapeutic abortion
advanced maternal age
abnormal presentation
maternal anemia
closely spaced pregnancies

1: (150 =- 305)

partial
complete
marginal
low

marginal just touches the cervix and partial covers some of the cervix

96%

Do not use around radiologists

chorioangioma
teratoma
hemangioma
hematoma
thrombosis
placenta extrachorialis
placental cysts
membranous cord insertion
battledore placenta

subchorionic fibrin depositions
NO CLINICAL SIGNIFICANCE

vascular malformation, Similiar to a hemangioma
most common placental tumor can lead to fetal hydrops

well-circumscribed mass; usually lobulated
hypoechoic
located within placental tissue
may contain calcifications

failure in development of the chorion villi persists

rare
placenta develpos as a thin membrane along the
periphery of the chorion along the entire gestational sac

increase risk of
placenta accreta
placenta increta
placenta percreta

1% to 2%

circummarginate
circumvallate

chorionic plate is surrounded by a thick ring

PROM
premature labor
placental abruption
hemorrhage

chorionic plate is surrounded by a thin ring
no clinical significance

less than 20%

subchorionic

intervillous thrombosis

cord inserts at placental margin into corion laeve
not protected my wharton's jelly

1% of pregnancies

IUGR

Interuterine growth regressor

Cord inserts at placental margin.
Not clinically significant
looks like baddmitten

7% of pregnancies

presence of one or more accessory lobes connected to the body of the
placenta by blood vessels

bilobate placenta

can rupture during labor
it can be left behind

connection between the placenta and the fetus

essential link for oxygen and nutrients

2 umbilical arteries
1 umbilical vein

week 9

surrounds the vessels within the umbilical cord to protect them

abdominal wall defect

prolapse
nuchal cord
true knots

hypogastric arteries

cord gets caught in the endocervical canal

cord wraps around neck

knots

1%

single umbilical artery

single umbilical artery

congenital anomalies (25 - 50 %)
perinatal death
premature delivery
IUGR
chromosomal anomalies

very aggressive at 20 week exam lookig for anomalies

follow cord from insertion to IIV

hypogastric ligaments

less than 4:1

.45 - .58

increases

fetal morbidity and mortality

normal pulsatile pattern
forward flow

be ready to go to OR but not emergency at this time...IN RED

Emergency ....OR

allatoic duct cysts
omphalomesenteric duct cysts
hemagioma
hematoma
mucoid degeneration of wharton's jelly
omphalocele
umbilical hernia

Allantoic cysts of the umbilical cord are extremely rare anomalies.

gestational diabetes
palpating fibroids

gestational trophoblastic disease

twins
open neural tube defect

fetal death
premature delivery
fetal anomalies
maternal bleeding
vas previa

placenta over cervix
A condition in which blood vessels within the placenta or
theumbilical cord are trapped between the fetus and the opening to the
birth canal, a situation that carries a high risk the fetus may die
from hemorrhagedue to a blood vessel tearing at the time the fetal
membranes rupture or during labor and delivery

zygote

monozygotic

Dizygotic

# of chorion
# of amniotic sacs

time of cell division

Dichorionic Diamniotic

Monochorionic Diamniotic

Monochorionic Monoamniotic

conjoined twins

thoracopagus

joined at the thorax

60%

56%

conjoined

Dichorionic Diamniotic
25%

10%

Monochorionic Diamniotic
73%

10%

Monochorionic Monoamniotic
2%

25%

70%

a small cystic collection appearing adjacent to gestational sac, that
appears to be a second gestational sac gets smaller and smaller.
Usually disappearing by the second trimester

fetus passes around 14 weeks
fluid is reabsorbed
lost twin is wrapped in amniotic membrane
pushed to the side by developing fetus
persists as a soft tissue mass

chorionicity
amnionicity
uterine response

twin to twin transfusion
entangles umbilical cord

twin to twin transfusion
stuck twin

Monozygotic twins
MCMA
MCDA

A/V shunt within the placenta
arterial blood of one twin is pumped into venous system of
the other twin

anemic
IUGR
oligohydramnios

LGA = large for gestational age
polyhydramnios
Too much glucose and urinates to try to rid of it
eventually leads to CHF and possible death

Discordant growth

concordant

best done in 1st trimeter

lambda sign
thick separating membrane

T sign
thin separating membrane

dizygotic
DCDA

DCDA

differences of estimated weight between monochorionic twins is
greater than 20%

differences of estimated weight between monochorionic twins is less
than 20%

10th & 90th percentile
Real world
5th & 95th

skiny head
common in twins

underestimates BPD

AKA Hydrops fatalis. Two sites of fluid accumulation or one site of
fluid collection and fetal ascites.

Hydrops fatalis

Immune Hydrops: results of Rh sensitivity

Nonimmune Hydrops: any hydrops in the absence of Rh sensitivity

results of Rh sensitivity

any hydrops in the absence of Rh sensitivity

Fluid collection
Fetal Ascites
Scalp Edema
Skin edema
Pleural Effusion
Pericardial effusion
Polyhydramnios
Large thick placenta
Enlarged fetal liver and spleen
Congestive heart failure

Rh- mother & Rh+ father = Rh+ baby
On second baby mothers antebodies cross the placenta and
cause hemolysis of eurthrocytes
baby tries to increase erythrocytes production
causing:
FCHF
Anemia
Edema

Rhogam shots at
28 weeks
3 days before delivery
anytime a procedure is done

Rogram
anti-D

ABO -Rh blood typing
antibody screening
Spectrophotometric evaluation of amniocentesis fro bilirubin
at 26 - 28 weeks

interuterine fetal death

interuterine fetal death

Fluid collection
Fetal Ascites
Scalp Edema
Skin edema
Pleural Effusion
Pericardial effusion
Polyhydramnios
Large thick placenta
Enlarged fetal liver and spleen
Congestive heart failure

Amniocentesis - Old method
Cordocentesis -

fetal hemoglobin
test for bilirubin
if elevated excessive destruction of red blood cells

baby is anemic
transfusion can be done during Cordocentesis.

mildly affected
deliverable at term

Fetus is affected but not an emergency
early delivery of intrauterine transfusion may be indicated

Emergency
immediate treatment

mother develops an immune response to fetal platelets
antibodes are produced
Baby has deficiency of cells for blood clotting
baby suffers from hemolysis

via cordocentisis

Nonimmune Hydrops
Not a result of Rh- sensistivity

Cardiovascular
Chromosomal
Twin to twin transfer
Urinary respiratory
G.I problems
Liver problems
Infectious problems
Placenta and umbilical cord problems
Parvo

dangerous to pregnant women before 20 weeks

Hydrops

Parvo

parvo

ultrasound

edema
* especially scalp edema
fetal ascites
pleural effusion
pericardial effusion
polyhydramnios
large thick placenta
fetal hepatomegaly
fetal spleenomegaly

Type I
pancreas does not produce enough insulin

Elevated glucose fires up fetal growth (FAT babies)
fetuses are frequently macrosomic
shoulder dystokia
Increased difficult labor
increased fetal death
incidence of neural tube defect increases 10 fold

Big ass baby
8 lbs 13 oz
4000 grams

frequent U/S

fetal macrosomia
polydramnios
increased fetal adipose tissue
caudal regression syndrome
congenital heart defects
Neural tube defects

Gestational Diabetes

...

small placenta
Growth retardation
oligohydraminos
placenta abruption

Pregnancy induced hypertension prior to 20 weeks

maternal proteinuria
edema
possible seizures

baby must be delivered immediately

seizures and/or coma

Hyperenemis graviarum
gallstones
peptic ulcers
trophoblastic disease
Twins = Higher hcg

dehydration
admitted for IV therapy

4-6%
25% of 4-6 will have UTI

progesterone dilates the ureteric smooth muscle
uterine compression of the ureters
*Sever hydronephrosis is ABNORMAL

germ cell tumor female counterpart of seminoma. Corpus Luteum of
pregnancy does not resolve

Cyst on ovary
8 – 10 cm

grow in response to estrogen. Can rapidly grow and undergo necrosis.
They can become large and interfere with pregnancy.
compression effects on baby
Causing pain and preterm labor

contractions resolve within 30 minutes
different blood flow patterns

absence of fetal tone after 20 weeks

infection
congenital anomalies
pre-eclampsia
placenta abruption
diabetes growth retardation
Rh sensitivity

15/20 : 100

TV heartbeat at 5.5 weeks

Ultrasound

overlapping cranium (spaulding sign)
liquefaction of brain material
skin thickening / scalp edema
dependency
gas shadowing - Roberts sign

overlapping cranium

gas shadowing within fetus

Onset of labor prior to 37 weeks gestation

PROM
Intrauterine infection
Bleeding
Fetal abnormalities
Polyhydramnios
Multiples
IUGR
Maternal diabetes/hypertension

RDS
Intracranial hemorrhage
GI Immaturity
Eating problems but

22 weeks

Estimated fetal weight

Greater than 500 g
*22 weeks

Watching for signs of fetal distress
Infection
Monitor and olighydramnios
meconium and in fluid

Looking the baby

4%

Tried to reduce the number of Breech Babies
Breech babies are more likely to have a C-section
The section increases risk, Length of stay and length of recovery
Breech babies have low APGAR scores

Cord prolapse
Prolonged labor - Increased risk of death
Complications - higher risk of chromosomal abnormalities

between 37 - 38 weeks

Re scan at 14 to 15 weeks to rule out rotation of mid gut

A wall defects tends to occur in boys on the right side

Free floating loops of bowel in the amniotic fluid

the intestines, liver, and occasionally other organs remain outside
of the abdomen in a sac
35 – 60% caused by chromosomal abnormaities (bowel)

intestines appear outside abdomen in pouch

7 weeks
choroid plexus is the dominant feature

12 - 14 weeks

omphalocele has a surrounding membrane
gastroschisis is in direct contact with amniotic fluid

Failure of closure of neurotube at cephalic end, brain is in direct
contact with amniotic fluid and dissolves.

Frog apearance
no parenchymal tissue is seen above the orbits

brain necrosis results from obstruction of ICA – lack of nutrients

Cystic mass in place of brain parenchyma

congenital endocrine disorder
ovaries do not respond to FSH & LH

Sign of Turner syndrome. Bad insertion of lymphatics into IJV.
Associated with Trisomy 12, 18, 21

Cystic mass in cervical region
septated

benign
Wharton's Jelly cysts
ophalomesentery duct cyst
Monitor for changes (can be caused by other abnormalities)

collection of blood from detached placenta
Prognosis – size dependent

secretes progesterone to support pregnancy until placenta takes over.
Less than 5 cm – normal
Greater than 5cm – intervention needed

Sonographic Appearance:
Septations

ampulla - 80%
fimbrae - 0.5%
isthmus - 15%
Cervix - 0.1%

10%

interstitial AKA Cornial
rarest and most dangerous
very vascular

PID
IUCD
fallopian tube surgery
inferitlity treatment
previous

Pain 97%
Vag bleeding 75%
palpable adnexal mass 50%

500 IU/L trans vag
1800 IU/L trans abdominal

lower than IUP

2 days 1st 6 weeks
3 days 6+ weeks

Doppler
ectopic - trophoblastic tissue lights up
corpus luteum cyst - lights up also

simutaneous intrauterine and ectrauterine pregnancy
Very rare
1:6000 / 8000 pregnancy

Ectopic pregnancy at cornual
Life threatening condition due to increased area vascularity and
possible rupture of tissue
SURGERY
RARE

But complex mass on the ovary
Differential diagnosis hemorrhagic corpus luteum cyst
RARE 0.5%

4%

46
6 weeks

a fertilized ovum that does not result in a embryo.
something goes wrong after implantation.
normal signs of pregnancy will occur

Large gestation all sac without inter gestation all anatomy
irregular shaped or abnormally shaped gestation all sac

90 to 170 bpm
Less than 90 bpm is very pour prognosis

Poor prognosis
Associated with babies that are starving baby that are starving do
not urinate

Empty uterus
No free fluid
No adnexal mass
hCG should be declining

gestational sac may be normal with embryo w/ no fetal heart rate
misshappen gestational sac

retained products of conseption

vaginal bleeding with a closed cervical OS in a preganancy of less
than 20 weeks.

hydatiform mole - growth that forms inside the womb (uterus) at the
beginning of a pregnancy. Partial (2-1) complete (1-0)
invasive mole - chorioadenoma destruens grows
into the muscular wall of the uterus
choriocarcinoma -

snowstorm late 1st
sac of grapes in 2nd

symmetrical
asymmetrical
10th (5th) percentile

previous
maternal hypertension
tobacco
uterine anomolies
placental hemorrhage

increased risk of antepartum death
perinatal asphyxia
Neonatal morbidity
later development problems

1st trimester insult
hypertension
diabetes

asymmetric
usually caused by placental insufficiency

BPD & HC normal
AC small

FL 90th percentile
AC below 5th

AC
liver is severely affected by IUGR

HC/AC ratio
EFW decreasing
ratio increases with increasing gestational age with IUGR

oligo< 5cm
poly >22 cm

decreased placental thickness < 1.5 cm
grade 3 before 36 weeks
NOT good method!

1% - 3%
missing limbs risk too

early (10-12 weeks)
results in 1 week
more options if early

disgnose spina bifida
chromosomal abnormalities
15 - 20 weeks

advanced maternal age
children with chromosomal abnormalities
AFT
U/S detected problems

clenched hands
5th middle phalanx hypoplasia
choroid plexus cysts
ventriularmegaly
thickened nuchal fold
cardiac anomalies
omphalocele
spina bifida
foot anomalies

Percutaneous umbilical cord sampling
difficult
done on patients when CVS and amnio inconclusive

experimental
florescent chromosomal markers into amniotic fluid
early detection of Trisomy 13 18 21
amniocentesis must be done after

fetal spine
GI tract
liver
kidneys
transported to mother placenta

ectopia corditis
anterior abdominal wall defect
bowel obstruction
amniotic band syndrome
twins
renal disorders
placental lesions
fetal heart disease - hydrops / ascites
Cystic hygroma
maternal & fetal liver disease
oligohydramnios
heredity
blood contaminated anmiocentesis
virus / infection
high blood pressure

Trisomy 13, 18, 21
fetus younger than expected
fetal death
hydatidiform mole
spontaneous abortion

15 - 18 weeks.

Edwards not good usually fatal

downs

Patau's syndrom