GUIDELINES FOR OBSTETRIC ULTRASOUND

1. 1st Trimester Guidelines - is it intrauterine & viable
Fetal Number - watch for double sac & yolk sac, twins etc
Gest age - CRL accurate to +/- 3-7d, 2nd trimester better
Morphology - endovag probe detects abn in every system
specificity may require waiting until 2nd tri
omphalocele, thick skin & anecephalic app all seen in 1st
Placenta - often difficult to be certain more than ant & post
Uterus & Adenexa - most important here, later more difficult

2. 2nd & 3rd Trimester Guidelines
Fetal Number - easier, but underestimation #1
Viability - 2 examiners should observe no heart tones x 3min
lack of fetal motion does not signify death
Fetal lie - relationship of fetal axis to uterine axis
longitudinal #1
Presenting Part - portion of fetus closest to cervix
Cephalic #1, other considered malpresentation, inc mort
Gest Age - if a part is abn it must be excluded
relate menstrual age & previous exams, consider IUGR
asses interval growth at >2wks or error likely
Amniotic Fluid - less in later stages, obese appear less
Dx of oligohydramnious only w NO fluid seen
Polyhydramnious often N, more common in twins
Amniotic Fluid Index - fluid collections measured in 4 quadrants
all are added together in cm & if <5 abnormal
Placenta - low lying placenta must be R/O w empty bladder
Trendelenberg & translabial also, follow if not certain
Malformations - most accurate at 20wks

NORMAL ANATOMY & MEMBRANES
Decidua Capsularis - endometrium covering gestational sac
Decidua Basalis - endometrium beneath placenta
Decidua Parietalis or Vera - endometrium distal to gest sac
Chorionic Cavity - largest portion of gest sac early
membrane has same origin as placenta, inseperably fused
Embryonic Disk - Amnion superior & yolk sac inf, all in chorion
Amnionic mem surround embryo, fuses to umbilical cord

GESTATIONAL AGE
Slight inc accuracy in 1st vs early 2nd trimester
Much less info availabe at 1st though

1. Gest Sac - detected at 2mm = 5wks, 10mm = 6wks, 1mm per day
Age in days = 30 + sac diameter in mm
"Double Sac" sign - 2 concentric rings around the normal gest sac
outer is decidua parietalis, inner is decidua capsularis & basalis
eccentric location best for DDx from pseudosac
gives very accurate dates if obtained between 5-6.5wks

2. Yolk Sac - 100% seen by 6wks, should not exceed 6mm

3. CRL - done at 6.5 - 10wks, age in wks = CRL in cm + 6
Beam divergence & splitting introduce error, exclude yolk sac
85% accuracy in predicting EDC +/-14d, considered the most accurate
BPD at 14-22wks & reliable dates by LNMP also 85% accurate

4. Cardiac Activity - begins at 22nd day P conception, 100% by 6.9wk
detectable by 6wks, embryo can be seen before this

5. Midgut Herniation - seen at 7-10wks, NONE P 12wks

6. B-hCG levels - 500-1500 IU/L at 5wks, double every 2 days


LANDMARKS IN GESTATIONAL AGE
Transabdominal
20mm gest sac - yolk sac seen
25mm gest sac - embryo seen
9mm embryo - heart activity, 6.9wks
1800iu BhCG - gest sac visualized
Transvaginal
10mm gest sac - yolk sac seen
15mm gest sac - embryo seen
6mm embryo - heart activity, 6.3wks
1000iu BhCG - gest sac visualized, earliest poss at 500iu
Heart Rate < 85bpm at < 10wks gest = demise
Age in days = sac diameter in mm + 30
Age in wks = CRL in cm + 6

THREATENED ABORTION
clinincal Dx of vaginal bleeding or spotting, uterine cramp
occurs during 1st 20wks w cervical os closed
occurs in 25% of clinically apparent gest, 50% will abort
progestinal drugs do NOT stop it, only delay
living embryo w CRL >5mm has 90% survival, <5mm 70%

1. Subchorionic Hematoma - seen in 25% w threatened abortion
Placetal Abruption doubles loss rate, most blood not retroplacental
larger collections distal to placenta less significant
accounts for 10% of vaginal bleeding in first 20wks

2. Embryonic Bradycardia - rate <85bpm assoc w 99% loss
Evaluate when >5mm only, if less w no heartbeat reasses in 4d
Confirm w sm embryos that you are indeed looking at embryo

3. Abnormal Yolk Sac - 80% abort when sac to small or distorted
Abn if not identified in gest sac >20mm, most seen by 10mm
Yolk sac often seen before embryo

4. Disproportionate Gest Sac - Increase proportional w hCG up to 8w
At 8wks gest sac at 25mm, hCG platues then decreases
Sac should be seen w trans abd when hCG at 1800mIu/ml
sac grows 1mm/d, hCG doubles every 2-3d
too lg w blighted ovum, dec hCG
If Amnion seen w/o vis of embryo ovum is blighted

5. Maternal Factors - Submucosal myomas, bicornate uterus
DES Daughters

6. Minor Predictive Factors - thin weak choriodecidual rxn
No double decedual sac & low postion of the sac
represent specific stages of abortion when clearly present
all a very subjective assesment though

7. Missed Abortion - retention of dead pregnancy >2mo

MASSES IN EARLY PREGNANCY

1. Uterine Fibroid - must be ditinguished from myometria contraction
tends to be more hypoechoic to adjacent myometria
attenuates the beam & is heterogeneous, does not change
Distorts serosal & endometrial layers, vs enodometria only
Doppler shows no vascularture, contractions very vasc

2. Ovarian Corpus Luteum Cyst - 2cm before preg, enlarge for up to 10w
may have loculations & thickened wall sim neoplasm
Malig is VERY rare in pregnancy, laporotomy only in 2nd tri

3. Gestational Trophoblastic Dz - usually not apparent until 12wks
a normal placenta may be seen, 2% assoc w fetus, usually triploidy
marked inc in B-hCG levels, stimulates lg bilat lutein cysts
25% become invasive

ECTOPIC PREGNANCY
Most are assoc w an adenexal mass, gest sac rarely seen
Fluid often identified in cul-de-sac
difficult to DDx from physiologic follicle rupture
B-hCG doubling rate slows, normally doubles every 2 days
Psuedosac - central uterine fluid collection, has only one decidual ring
DDx - abnormal or blighted gestations often similar
Extrauterine with concominant intrauterine in 1:10,000

2ND & 3RD TRIMESTER GESTATIONAL AGE
A simple average of all gives accurate date, +/- 8% of calc
be sure to use the opportunity to eval all systems
A known age by menstrual Hx is NOT superceded by US age
US still useful as growth index

1. Biparietal Diameter - transverse at cavum sep, thalmi & choroid
preferable w fetus in occiput transverse position
Accurate to +/- 1wk before 20wks, +/-2wks after
Shape changes due to mult gest, ruptured mem, term preg
BPD accuracy falls drastically
BPD accurate predictor if Ceph index 75-80
Cephalic Index = BPD/fronto occipital diameter X 100
2.0cm @ 12wk +/- 1.0wks
4.8cm @ 20wk
7.6cm @ 30wk +/- 2.0wks
9.5cm @ 40wk

2. Head Circumferance - shape independent, more accurate overall
ease of measurement also makes it a good parameter
Most useful as a comparison with AC to asses fetal well being
HC/AC 1.2 @ 16wks
1.0 @ 36wks

3. Abdominal Circumference - trans at umbilical part of L portal
also thru stomach, traced at outer margin
distortion poss w transducer, contraction, oligo etc
most variable parameter, susceptable to growth delay change
10.0cm @ 16wks +/- 1.9wks
15.0cm @ 20wks +/- 2.0wks
26.0cm @ 30wks +/- 2.2wks
36.0cm @ 40wks +/- 2.5wks

4. Femur Length - measured ends of bone should be blunt
epiphysis should not be included
bowing seen w osteogenesis imperfecta, dwarfism, hypophos etc
fractures can also preclude use as measurement for age
20mm @ 16wks +/- 3wks
32mm @ 20wks
57mm @ 30wks
80mm @ 40wks +/- 2wks

MULTIPLE GESTATIONS

1. Dizygotic - 1:20 in nigeria, 1:80 whites, 1:150 japanese
placentas may fuse but NO vasc anastamosis occurs

2. Monozygotic - 3.5 in 1000 for all
Dichorionic Diamniotic - morula splits in 1st 4 days
25%, placenta can be split or fused, 10% mortality
Chorionic Peak - triangular mound of placenta @ fusion
Thick mem between w 2 layers of chorion & 2 of amnion

Monochorionic Diamniotic - blastocyst polarizes at 4-8d
75%, single placenta only, 25% mortality
divides before amnion forms over embryonic plate
mem very thin & wispy, may not be visualized
Stuck Twin - oligo in 1 twin causes adherance of mem
mem not visualized & twin will not shift w gravity

Monochorionic Monoamniotic - blastocyst polarizes at 8-13d
<2%, very high risk, 50% mortality
Any fused monozygotic placenta ALWAYS has art anas
Tx very aggressive, confirm w contrast in amnion
will then concentrate in gut of both twins on CT
Cord tangleing freq, C-section at 32wks reccomended

3. Morbidity & Mortality - 2X singleton, triplets 4X worse
1500g or less in 10%, only 1% of singletons
3rd trimester IUGR freq due to 3000g carrying max for uterus
use twin growth charts to take this into account
Twin transfusion, twin embolization & acardiac parabiotic syn
Fetus papyraceous - hylanized twin remenant
Monozygotic twins have inc congenital abn over dizygotic
clubfoot & Crowding abnormalities occur in both

4. Monitoring Twins - Biophysical profile most useful
Breathing, fetal movement, tone & adequacy of amniotic fluid
should be performed twice weakly w any sign of abn
Abd Circuference >20mm different indicates prob wt discord
monitor cervex freq, circulage may be needed
Amniocentesis - inject indigo carmen into 1st sac done
stress causes lungs to mature, if lg twin mature smaller is
5. Monochorionic Twin Syndromes - all have vasc comm
Twin Death - even sm venous anastamosis allows shunting
pressure forces live twins blood to dead twin, rapid death
NEVER perform selective termination w monochorionic twins

Twin Transfusion Syndrome - A-V comm in shared cotyledon
discrepancy in amniotic fluid levels #1 finding
15% discord in wt, lethal in early acute form
Donor twin sm & anemic, poor renal perfusion, oligo
Recipient twin lg & vigorus intially
CHF, hydrops & death may result from circ overload
Polyhydramnious can cause early labor
Select Amniocentesis of lg twin Aides both
Sm twin regains fluid & circ pressure

Twin Embolization Syn - dead twin can allow mult emboli
Brain, sm intestine & kidneys freq affected P twin death
Vein to vein anatamosis more than art to art

Acardiac Parabiotic Twin - fetus w no heart cont to grow
paired art-art & vein-vein anastamosis required
upper body & head very abn or absent, (lower perf first)
High output cardiac failure & hydrops threatens N twin
Use volume reduction amniocentesis or ligate acardiac one

6. Conjoined Twins - division of disk P 13d, 1:50,000
pattern of fusion variable, rarely seperable

7. Heterotopic Multiple Gestation - inc w assisted fertility drugs
Coexistent adenexal abn or ascites should alert you

8. Selective Reduction - intracardiac or thoracic injected KCl
Use anomalous embryo or one w smallest sac, karyotype if poss
Monochorionic twins if accom by others should be selected
avoid killing the presenting fetus, may cause preterm labor
high ant easiest, loss of all occurs in 20%

9. Superfetation - very rare, 2nd ovum fertilized at diff month
Superfecundation - 2 fertilized by different fathers

INTRAUTERINE GROWTH RETARDATION
occurs in 5% of low risk population

1. Symetric IUGR - Fetal factors, 1st tri insult, CHD, chrom or infec
Fetus sm thruout pregnancy, outcome not altered
Chrom Abn - 5%, detectable very early w serial 8 & 11wk exam
CRL decreased early
75% of IUGR due to lower than normal growth potential (john)
Fetus concieved late in cycle will be one wk behind

2. Asymetric IUGR - Maternal factors, placental, smoking, vasc Dz, diabetes
placental insuf causes 20%, occurs in 2nd or 3rd tri
Relative sparing of head, abd & soft tissure dec most
HC/AC 1.2 @ 16wks, 1.0 @ 36wks
Must be based on growth not overall size

3. Detecting Fetal Distress - if IUGR detected must asses fetal well being
Biophysical Profile - Breathing, Motion, Tone & Adequacy of fluid vol
Breathing most sensitive - stops w any distress, also stops w sleeping
very nonspecific, if not seen reasses in 30min x4 until seen
well being has not been proven until all 4 seen
Motion 2nd most sensitive, loss of Tone 3rd
Oligohydramnios - specific for severe fetal distress, Renal Failure
can be seen post dates, but not a good sign in late 2nd or early 3rd

Non-Stress Test - 30min observation of fetus while awake & moving
should see cardiac rate inc of 10-15 beats on 3-4 consecutive movements
inc should be sustained for 40-60sec

Umbilical Artery Doppler - S/D Ratio, <.5 in 1st trimester, <.2 in 3rd
Absent or reversed diastolic flow assoc w severe stress

MACROSOMIA
Large for gest age at birth, >4000g or >90th percentile
Morbidity assoc w birth trauma, asphyxia & prolonged preg

1. Symetric - prolonged pregnancy or genetic factors

2. Asymetric - Diabetes causes dispropotionate lg abd
only 2% of macrosomic fetuses are from diabetic mothers
detect early, massive growth can occur in 39th & 40th wk

FETAL NEURAL AXIS
Lat vents dominated by echogenic choroid plexus
Solid nueral tissue unexpectantly hypoechoic
ALWAY IDENTIFY - cavum septum, atria of lat vents & cist mag
Cavum septum pelucidi usually present in newborn up to 2mo
Cavum septum vergae often present in premie

1. Dandy-Walker Syndrome - spectrum of abn Cb & 4th vent abn
Vermian dysgenesis & expaned 4th vent shifts tent upward
Cyst is the post medullary vellum, an ependymal lining
Detected at 20wks gest, assoc hydroceph & CC dysgenesis
The wider the spread of the Cb hemispheres the worse the prog
DDx - Arachnoid cyst, displaces Cb in bloc, no spread
Large Cisterna Magna also w Cb hypoplasia & comm hydroceph

2. Agenesis of the Corpus Callosusm - develops ant-post, 12-17wks
first detected at 20wks, only complete form detectable
Septum Pellucidum formed concomitantly inf & between fornix
Probst bundles run along medial vents, spread them lateraly
Colpocephaly - enlarged atria & occipital horns of lat vents
due to maldevelopment of surrounding WM tracts
Always present w holoprosencephaly, karyotyping indicated
MR results in 70% & Seizures in 60%, Hydroceph poss
Often associated with interhemispheric or periventricular cysts

3. Holoprosencephaly - abn forebrain w freq facial anomalies
Abn cleavage & diverticulation of prosencephalon
does not properly form diencephalon & telencephalon
evagination of optic vesicles & olfac bulb also abn

Alobar - single vent, fused thalmus & corpus striatum
corpus, fornix, falx, optic tracts & olfact bulb absent
midbrain, stem & Cb N unless hydroceph compresses

Semilobar - rudimentery occipital horns, falx & fissures

lobar - fusion only in rostral portion, thalami seperate
absent septum pellucidum allows vents to comm, corpus part

Face predicts brain but brain does not predict face
DDx - hydrocephalis, causes wide spread of thalmi by 3rd vent
demonstration of frontal horns excludes holoprosencephaly

4. Congenital Vascular Insults
Hydrancephaly - complete destruction of cortex & basal gang
sm head usual unless hydrocephalic, etiology carotid occ
med occipital lobes may be spared by post circ
DDx - prolonged hydrocephalis, thin rim of cortex remains
Alobar Holoprosenceph - Falx never present

Porencephaly - destroyed necrotic segment comm w adj vent
NO mass effect as may be seen w arachnoid cyst
Cystic encephalomalacia if no comm to vent
Can have mult cystic areas from mult events

Schizencephaly - gray-lined cleft to ependyma, open or closed
heterotopic gray nodule often seen near vent
actually a defect in cellular migration, prob vasc cause

5. Hydrocephalus - inc vol due to obstruction, comm or non-comm
inc pressure relative to intracranial venous sys
Dx - Atrium of Lat vent >10mm, choroid does not fill, dangle
Vent asymetry erroniously seen due to prox reverberation
Non-comm much more common in fetus, aqueductal stenosis
1/3 due to myelomeningocele or encephalocele
DDx - Non-obstructive Ventriculomegaly, Hydranceph, holopros
distinction often difficult w fetal US
LOOK for additional abnormalities of assoc syndromes

6. Space Occupying Lesions
Neoplasm - very rare in neonates, freq hydroceph
Teratoma - #1, often cystic but usually mass assoc
Glial type - #2, may sim hem or necrosis

Arachnoid Cyst - congenital less common than aquired
abn zone of development between pia & arachnoid, rare
Mass effect always seen, no vent comm as in porenceph

Choroid Plexus Cyst - freq at 16-20wks, at glomus of choroid
.5-2cm, often multiloculated, rarly expand vent,
almost all will regress, slight inc assoc w syndromes

AVM - causes heart failure & brain infarct due to "Steal"
Vein of Galen Aneurysm seen at quadrigeminal cistern, dopp

7. Intracranial Hemorrhage - 50% of premies under 1500g, <32wks
occur 1-7d P birth, sudden BP changes believed etiology
I - in germ matrix
II - into vent
III - hydro
IV - parench
only grade III or IV seen in utero, severe stress

8. Open Neural Tube Defects - most common congenital abnormality
More common if previous sib affected, 90% spontaneous
Sonography serves as 2nd level of testin P positive AFP

Anencephaly - #1, 4:1 female, ceph end of tube does not close
50% have polyhydramnious after 26wk
DDx - microcephaly, cranial vault still present
Amniotic band defect to skull, usually asymetric

Encephalocele - least common, ectoderm fuses w neuroectoderm
mesodermal defect allows herniation, 75% midline occipital
DDx - cystic hygroma, no cranial defect, cystic teratoma

Myelomeningocele - #2 open tube defect, lumbar & sacrum #1
prognosis worse w higher & larger lesions
Sac may be visualized, wide pedicles, clubfoot
Chiari II & lemon shaped skull always, #1 hydroceph etiol
Cisterna magna will always be greater than 10mm
"Banana" shaped pathog

FETAL FACE

1. Embryology - forms between 4-8wks from 1st branchial arch
Stomodeum membrane cannulates at 26d to comm w pharynx
insuff migration of neural crest cell into 1st arch cause abn
1st arch syn also assoc w congenital heart defects
features identified by US by 10-11wks, coronal best for lip

2. Facial Clefts - max prominence fails to fuse w intermax seg
1 in 1000 births, rises to 4% if sib affected
50% have assoc congenital abn, freq in tri 13 & 18
incomplete & unilat cleft less often assoc
Median Cleft - unusual form assoc w holoprosenceph

3. Fetal Mandible - Midline sagital view demostrates best
Micrognathia assoc w several 1st arch syndromes
Treacher Collins Syn - auto dom, slanted eyes, low ears
Goldenhar Syn - hemifacial microsomia
4. Fetal Orbits - can be measured but usually subjective
Hyptoelorism - assoc w severe brain malformation
holoprosencephaly can result in cyclopia & proboscis

5. Maxillary Hypoplasia - caused by phenytoin

6. Frontal Bosing - Achondroplasia or craniosynostosis
Check extremities carefully if this is observed

MUSCULOSKELETAL
simple femur measurement reveals many abn, ie short in downs
N configuration of extremities by 10wks, ossification begins
structure & fxn of joints depends on N movement during gest
Prox Humeral epiphysis never calc before 38wk
if these are seen you know the lungs are mature
shorter than 2 SD below mean at risk for dwarfism
some not evident until after 22wks, earlier esp w lethal form

LETHAL SKELETAL DYSPLASIAS
many described but 3 account for the vast majority

1. Thanatophoric Dysplasia - #1, 1 in 4000 births, Auto Rec
Cloverleaf skull most distinctive, seen in 14%
Marked foreshortening, limbs held at 90 deg angle to body
Most present w polyhydramnios, lg for dates
DDx - Homozygous Achondroplasia, only in affected parents

2. Achondrogenesis - Auto Rec, 1 in 40,000
Severly limited or absent skeletal ossification
Profound limb foreshortening II' to disorganized cartilage
Combined absent vert body & calvarial ossification diagnostic
several other dysplasias may have one or the other

3. Osteogenesis Imperfecta - disorders w defective collagen
Types II & III are lethal, both auto rec
Accordian bones due to innumerable fractures
Exuberant callous formation typical of this dz
Hypomineralization esp of calvaria & platyspondyly poss
calvaria may be compressable


DYSPLASIA'S W GOOD OR VARIABLE PROGNOSIS
Tend to present later in gestation, diff to detect esp <22wks

1. Heterozygous Achondroplasia - 1 in 30,000, Auto Dom, 80% spont
Moderate micromelia, discrepancy relative to BPD best sign
Basilar invag, saddle-nose, kyphosis, Spinal Stenosis
"Trident Hand" - short prox & middle phalanges of all fingers

2. Asphyxiating Thoracic Dysplasia - Rare, Auto Rec w variable exp
Can vary from lethal to No resp Sx, thoracic size dictates
mild micromelia usually, pattern sim to het achondroplasia
Polydactly in 14%

3. Chondroectodermal Dysplasia - Auto Rec, mostly in Amish comm
Mild limb shortening, 50% w congenital heart Dz
less severe than short-rib polydactly syn, good prognosis

4. Diastrophic Dysplasia - Auto Rec, variable severe to mild
Cleft palate & fixed elbow & phalanx joints common
"hitchhiker thumb" due to extended thumb
Kyphoscoliosis can inhibit cardiac & pulm fxn, N mentality

5. Osteogenesis Imperfecta - types I most common, N limb length
Fx seen in only 5% of neonates, bone bowing more common
Type IV - Same except no blue sclera or deafness
Vaginal delivery presents only minimal risk

FOCAL LIMB OR EXTREMITY BONE LOSS
Not bone dysplasias

1. Radial Ray Defect - mult disorders lead to thumb & radius agen
Tri 18 & 13, Fanconi, Holt-Oram Syn etc
Humerus may also be shortened or absent

2. Amniotic Band Syndrome - 1 in 1200, freq assoc w spont abortion
rupture of amnion causes transient oligo, fetal parts caught
Large bizarre defects can occur in any portion of fetus
Limb-Body Wall Complex - related but not proven to be same
invariable fatal defects in thorax & abd

3. Roberts Syndrome - called Pseudothalidomide syn in mild form
complete limb absence w only fingers on shoulder
bilat cleft, hypertelorism, microcephaly & growth retardation

4. Sirenomelia - "Mermaid Syndrome", lower ext fusion
a manifestation of caudal regression syn, severe oligo
Fatal bilat renal agenesis or multicystic kids

5. Sacral Agenesis - increases in infants of diabetic mothers


CONTRACTURE & POSTURE DEFORMITIES
Fetal Akenesis Deformation Sequence
Result from absense of prenatal joint movement
Physical causes, abn Nerves, abn muscle or defective con tis

1. Arthrogryposis Multiplex Congenita - mult ext contractures
Oligohydramnios most common cause, but any of above poss
Curare administered in late fetal life also cause

2. Pterygium - webbing of skin across a joint, II' to movement res
Popliteal most common


HAND & FOOT DEFORMITIES

1. Clubfoot - 1 in 250, often assoc w other anomalies esp w akinesia
Talipes Equinovarus - plantarflexed & varus #1
seen as early as 13wks

2. Clinodactly - permenant deviation or deflection of finger
often assoc w overlap, suggests trisomy, not pathognomonic

3. Polydactly & Syndactly - help in narrowing DDx of other abn
w dysplasia assoc w short-rib polydactly syn, NOT Thanatophoric
assoc w chondroectodermal dys NOT asphyxiating thoracic dys
Syndactly difficult to confirm as isolated finding

FETAL HEART- complete text under "heart" section of the "chest" file
best imaged at 18-22wks, structure not possible before 16wks
image thru the fetal abd if poss

1. Risk Factors - prev sib affected, maternal diabetes or drugs
fetal hydrops, arrythmia or other abnomality
overall 1% have cardiac anomalies, 2% have arrythmias
80% die in utero or shortly after of assoc complications

2. Structural Defects - Atrioventrecular septal defects #1
Inc Vasc - No Cyanosis, eventually lead to Eisenmeinger phys
ASD
VSD
PDA
PAPVR - Type I, snowman

Dec Vasc, CYANOSIS
Tet - overiding aorta, pulm insuff, ASD & VSD
Trans
Truncus
Tri Atresia & Pulm atresia or stenosis
Tingle
Ebstein Anomaly - lg R atrium preventing flow to R vent
N Vasc, NO Cyanosis
Aortic sten or Atresia
Coarctation - reverse 3 & rib notching
Mitral Stenosis or Insuff
Cor Triatriatum - lg L atrium w extra chamber impeds flow
TAPVR - Type III, Subdiaphragmatic
Hypoplastic L Heart

3. Arrythmias - total block, atria beat at 130, vent at 65bpm
SV tachycardia due to atrial flutter - hydrops & cardiac fail
drugs such as dig given to mother, make her theraputic
rates slower than 80 indicative of futher abn
isolated PVC's freq & transient, inc w caffiene & smoking

FETAL THORAX
Clavicles provide anatomic marker sup, diaph inferior

1. Fetal Lung Development - #1 determinate of fetal survival
Gest Age most accurate predictor of lung maturity
Oligohydramnios can delay maturation
Need 3 elements - space to grow, fetal resp & N amniotic lev
Pulmonary Hypoplasia results w/o these elements
If a mass is large enough to be seen it is causing comp
16-18wks - normal number of bronchi have formed
24wks - inc airspaces & capillaries, earliest possible viable
Surfactant prod begins - Lecithin/Sphingomyelin ratio >2
After 24wks - flattening of pulm epithelium, improve gas exch
US - lung starts less echogenic than liver, becomes more late
Alveoli continue to multiplly thru adolescence
Grade III placenta indicates lung maturity in 100%

2. Congenital Diaphragmatic Hernia - diaph forms at 6-14wks
3 structures must fuse with the pleuroperitoneal mem
Septum transversum, body wall & dorsal mesentery of esoph
92% are postlat & unilat, 50% have assoc anomalies
Pulmonary hypoplasia from Mass effect compressing lung
Arterial musc hyperplasia causes pulm htn & persistent PDA
US - Dx by visualization of abd organs in chest
Sm abd circ, No stomach in abd or shift of mediast also
Polyhydramnious freq presenting complaint
Fetal Hydrops indicates poor prognosis

3. Cystic Adenomatoid Malformtion - rare, hamartoma
Large & noncompressible, can shift mediast & compress IVC
Polyhydramnios, Fetal Hydrops & Pulmonary Hypoplasia assoc
Microcystic - Hyperechoic & solid appearing on US
poorer prognosis, generally do well if survive delivery
Macrocystic - percutaneous aspiration poss, usually reaccum
Have been succesfully resected in utero
occasionally regress in utero w/o intervention

4. Pulmonary Sequestration - bronchopulmonary foregut abnormality
NO communication w bronchial tree
Extralobular - only 25% but only ones detectable in utero
Ectopic blood supply & enveloped by it's own pleura
Aorta to inf pole of mass, helps DDx from CAM or CDH
90% on Left in post basal seg, 2.5% outside thoracic cav
60% assoc w other anomalies including diaph hernia
Intralobular - 75%, may be aquired, No assoc anomalies
much less common in neonate
Polyhydramnios & Fetal hydrops due to mediast & esoph compres

5. Bronchogenic Cyst - rare, foregut abn which occurs at 4-6wks
Abn budding of the anterior portion of forgut to bronch
mid portion goes to esoph dup & post to neurenteric cysts
NOT assoc w other anomalies, Diff to detect in fetus
May enlarge in infancy causing resp distress

6. Congenital Bronchial Atresia - focal obliteration of trach part
Usually in L upper lobe, obs lung distends w fluid
Fetal Ascites assoc II' to IVC obs, 100% mortality

7. Pleural Effusion - poor prognosis when II' to other anomalies
I' effusion usually chylous, better prognosis but still 50%
fluid is clear because fetus does not ingest fat
occurs initially as isolated finding & very large
pulmonary hypoplasia, hydrops etc still assoc late
Drain in utero, resolves spontaneously P birth w C tube

8. Congenital Lobar Emphysema - 40% occur in L Upper Lobe, 35% RML
1/3 present at birth, most present before 4mo, 3:1 male
Etiology - dysplasia or def of bronchial cartilage
obs, inflam & or mucous, overinflation from ET
compression from PDA, aberrant L pulm art or dilated pulm art
CXR - hazy masslike opacity due to slow clearing of fluid (1-14 days)
hyperlucent expanded lobe which compresses adj structures

FETAL ABDOMEN

1ST TRIMESTER
II' yolk sac vis in ceolom from 5wks to 14wks
Vitelline duct remenant, becomes Meckel's divertic in 2%
Meconium peritonitis may result from Meckel's rupture
Allantois is small nonfxn outpouching of yolk sac
Intestines herniate into cord at 9wks, back by 13wks
rotate 90deg on SMA axis while out, 180 more coming in
Umbilical Vessels - enter abd just ant to bladder
Umbilical vein empties into ductus venosus & portal sys
Persistent Right Umbilical Vein - assoc w lethal anom
Ductus Venosus - conduit from portal to systemic veins
40% bypasses liver thru this, other 60% thru portal
Umbilical Art - enters int iliac arteries

2ND & 3RD TRIMESTER

1. Hepatobiliary System - 10% of fetal mass at 11wks
primary site of hematopoesis until 14wks, then begins bile
Ductus venosus & hepatogastric lig sep caudate from left lobe

Calcifications in liver - tumor, vasc insult or infection
Often asym if no assoc abn can be detected
Diffuse Branching calc due to hepatic infarcts
Toxoplasmosis & Herpes simplex
Hemangioendothelioma, hepatoblastoma, teratoma, adenoma
Hemangioma - may appear cystic

Choledocal Cyst - type I cystic dil of CBD most common
assoc w intermitent biliary obs & severe biliary cirrhosis

Gallstones - rare, usually resolve spontaneously, NO Sx

Biliary Atresia - nonvis of GB in neonate, not detected fetal
etiology unknown, possible aquired via viral infection

2. Spleen - identified at 18-40wks, isoechoic w kidney
Splenomegaly - Rh isoimmunization, CMV, premature mem rup
Polysplenia Syn - No single spleen, multiple sm spleens
assoc w complete heart block & congenital heart Dz
3. Kidney's - seen by 18-22wks, more in GU section

4. Adrenal Glands - 20x there relative adult size at birth
seen as large striations lat of spine at level of stom
Fetal Zone of Adrenal Cortex - 80% of bulk of gland
forms a thick outer hypoechoic zone along w perm cortex
Origin of neonatal adrenal hem, Zone gone within 3-12 mo
Inner Zone - echogenic medulla
Adrenal Cysts - rare, resolve spontaneously P birth
PITFALL - don't mistake them for kidneys in renal agenesis
gland elongates and fills space that kidney should occupy

5. GI Tract - swallowing starts at 12wks, detected in stom by 16wk
If stomach not visualized by 19wks abn is assumed
swallow up to 750ml per day by term
Peristalsis - usually seen by 27wks, less echogenic bowel

Meconium - often vis in dist sm bowel after 16wks
appears echogenic & bulky, "fetal abdominal pseudomass"
Accumulation causes colon to inc diameter thru gest
Passage in utero - only occurs P 37wks, stress or Norm?
Meconium Ileus - sm bowel obs assoc w cystic fib, 1:2200
ileum dilated, microcolon from disuse, atresia poss
Echogenic Abdominal Mass of sm bowel freq presenting
Meconium peritonitis II' to rupture, calc seen within 10d
Cystic fibrosis is etiology in only 10%

Gastric Pseudomass - Aggregates of swallowed cells & debri
Occur before coordenated active peristalsis

Absent Stomach - If not visualized by 19wks abn is assumed
Mechanical obs - esoph atresia #1, chest mass, facial clefts
CNS abn preventing swallowing, Oligohydramnios

Esophageal Atresia - occurs at seperation from trach at 6wks
1:2500 births, etiology unknown, 5 types
Type B #1, blind prox & tracheoesophageal fistula to dist
Type A - blind-blind, C - forms H, D - fistula prox, E -both
Fistula will allow fluid to enter stomach, 50%
Vertebral, Anal, Cardiac, TracheoEsoph, Renal & Limb anom in 50%
Proximal esoph pouch may be observed but difficult w US
Duodenal Atresia - 1/3 of sm bowel atresia, 1:10,000
Failed recannulization, 30% trisomy, IUGR in 50%
Dilated stomach & prox duodenum, usually at ampulla in 2nd
biliary & pancreatic duct atresia & malrotatin in 50%
Polyhydramnios in 50%
Possible ischemic event esp if in 3rd & 4th portion
NO assoc w other anomalies
36% mortality but most w other abnormalities assoc

Jejunoileal Atresia - 1/3 each between prox jej & dist Ileum
occur in 1:5000 live births
Polyhydramnios freq, usually less severe w more dist obs

Megacystis Microcolon Intestinal Hypoperistalsis Syndrome
rare lethal anomaly, 80% female, Polyhydramnios freq
Dilated bladder w no obs, sm bowel dil, malrotated microcolon

Chloridorrhea - auto rec, transport of chloride from bowel dec
profuse chloride diarrhea results, fluid filled loops


6. Colon & Anorectal Defects
6% in 3rd tri have "presacral mass" of mec filled sigmoid

Anorectal Atresia - imperforate anus mildest, infralevator
Supralevator lesions - high termenation above sling
more common & assoc w GU abn, vesicoenteric fistula
Fistula cause enterolithiasis & bizarre cystic masses
Atresia assoc w dist bowel dil, look for VACTERL anomalies

Persistent Cloaca - rare, always in females, abd wall intact
Urorectal septum fails to join cloacal membrane
Mesonephric & paramesonephric duct development altered
ectopic ureters, duplications & atresias
assoc w spinal anomalies, 10% have esophageal atresia
US - shows bizarre bilobed pelvic mass

Microcolon - seen w aganglionosis, meconium ileus & ileal atresia
also w infants of diabetic mothers
not assoc w processes which occur late such as intussusception

7. Ascites - best seen in subhepatic recess & flanks
rare in pelvis because it is so small
integumentary edema, pleural & pericardial eff assoc
isolated w bowel perf or urinary bladder rupture
Pitfall - thin rim of lucent tissue on ant surface of abd
NO outline of the falciform & is not between ribs & liver
Urine #1 - usually due to post urethral valves in a male
UPJ & UVJ also poss, ruptures at fornix of calyx

8. Calcifications - neuroblastoma, teratoma, hamartoma, viral inf
Meconium Peritonitis - assoc w atresia, volvulus etc
develop in 10 days, before this only ascites seen
look bad but midgut anomalies have less assoc w VACTERL
As an isolated finding it has very little morbidity

9. Abdominal Cysts - rarely malignant, Teratoma is the exception
Ovarian cysts can be quit high in the abdomen & large
Mesenteric cysts, duplications, choledocal & urachal cysts
largest cysts are usually urinary

10. Malrotation - narrow attachement of mesentery
predisposes to midgut volvulus & bilious vomiting
Ladd's Bands - peritoneal band fixating the high riding cecum
crosses the 2nd or 3rd portion of the duodenum
NO lig of trietz is present
Diaphragmatic hernia, gastroschisis, omphalocele & eventration assoc
polysplenia also seen as well as two left lungs


ABDOMINAL WALL DEFECTS
C-section delivery rarely improves outcomes
VACTERL - Vert, Anal, Cardiac, TracheoEsoph, Renal & Limb

1. Umbilical Herniation - N at 8th wk & back by 12wks
Midgut grows faster than abd wall, cranial limb grows faster
Rotates clockwise 90deg on the way out, sm bowel returns 1st
Colon rotates additional 180deg coming back, 270deg total

2. Gastroschisis - Right paraumbilical defect involving all layers
Sm bowel herniates, by definition is nonrotated w no II' fix
kinked vessels may cause ischemia w assoc jej atresia etc
No mem covers bowel but matted & fibrous, high a-fetoprotien
urinary & liver may be included but rare
Ascites NOT present, cannot accumulate
Most are isolated finding, poss due to vasc insult to wall
7% w VACTERL defects, much less than omphalocele
US - mult free floating loops of bowel, cord inserted to L
Early identification allows near 100% survival
DDx - ruptured omphalocele or blood clot

3. Omphalocele - Exomphalos, herniation into umbilical cord base
Parietal peritoneum cover, P 10wks amnion & Wharton's jelly
70% assoc w other anomalies, predominantly chromosomal
freq still birth, 50% die but good prognosis if isolated
Usually found on survey for elev a-fetoprotien
US - smooth mem covered mass, cord inserts into mass
umbilical vien can be seen passing thru it

4. Beckwith-Wiedemen Syn - EMG, Exomphalos-Macroglossia-Gigantism
A group of disorders with these 3 findings in common
75% have E (4% of all omphaloceles), 97% have M, 32% G
hemihypertrophy, hepatosplenomegaly & cardiac anom also
Placental Endocrine Dysfxn - insulinlike growth factors sec
causes visceromegaly etc, Renal cysts & Wilms tumor assoc
US - Omphalocele most obvious, usually prompts other findings
Macroglossia seen in coronal, tounge N if not beyond gums
Suffocation is a freq complication at birth
Normal intelligence if they survive birth
5. Pentalogy of Cantrell - Thoracoabdominal ectopia cordis
Omphalocele assoc w an ectopic heart are the 2 main defects
other 3 are pericardial, ant diaph & inf sternal defects
trisomies, vert defects & internal cardiac defects assoc
Defect in lat mesoderm folds at 28-32 days
If detected intrauterine 100% fatal, minor defects repairable

6. Cloacal Exstrophy - bladder extrophy, imperf anus & vert defect
Omphalocele always present, meningocele & 2 vessel cord freq
Urorectal septum dosn't form, urogenital sinus & rectum fused
infraumbilical ant abd wall & genital tubercles cannot dev
Clubfoot, multicystic kids, hypoplastic chest, diaph hern
US - genitals & bladder split & divided, empties to amnion
DDx - amniotic band, sacrococcygeal teratoma, body stalk anom

7. Amniotic Band Syn - variable, rings, adhesions & entanglements
can be assoc w surg but most are spontaneous
poss due to early amnion rupture & transient oligohydramnios
Adhesion to sticky mesoderm from chorion surface
anomaly within fetuses cannot be excluded as etiology
Inc occurance w collagen disorders esp Ehler-Danlos Syn
US - cephaloceles, facial clefts, amputations, scoliosis
constricting rings of fingers & toes most freq finding

8. Short Umbilical Cord Syn - limb-body wall or body stalk anomaly
abnormalities involving failure of closure of ventral wall
Adhesion to amnion & persistence of extraembryonic coelom
short or absent umbilical cord, spine, limbs, cranium, etc
Gross evisceration of chest & abd contents occurs
Poss due to vasc insult at 4-6wks, karyotype Normal, 100% die
US - mass of organs & membranes w very little fluid

GENITOURINARY SYSTEM
Ureteral bud outpouches from wolfian duct at 6wks
Caudal cloaca narrows & elongates to form ureter
15 generations of branching forms calyces & col tubules
induces metanephric blastema to form nephrons at 10wks
Urine produced by 16wks, most of amnion by 2nd half of gest
bladder fills and empties every 25min, max 50ml/hr at 40wk
Oligohydramnios most sensitive indicator of GU Dz
90% of kidneys detected by 20wks, as early as 12wks w vag
span 4-5 vert bodies w prom lobules, length in mm = wks
should not exeed 1/3 the diameter of the abd
Ureters not N visualized, touch spine if dilated
beware of psoas musc, triangular & may mimic dil ureter
Unilat probs occur prox to ureteral buds, good prognosis
Bilat probs occur at level of cloaca, hearald genetic defect

1. Bilateral Renal Agenesis - 1:4000 births, Oligo seen P 16wks
Absence of bladder better than absence of kidneys for Dx
urachal divertic may mimic but does not empty & fill
Adrenal glands may assume oval elongated shape & mimic kids
ID of hypoechoic renal pyramids excludes this or bowel
VACTERL anomalies freq assoc, pulm hypoplasia due to oligo
Potter's Syndrome - the pulm hypoplsia etc caused by oligo

Severe Hypoplasia - has sim clinical course but sm kids seen

Unilateral Renal Agenesis - 20x more common than bilat
compensatory hypertrophy occurs contralat, N urine production
rare assoc w other GU anomalies

2. Crossed Renal Ectopia - 1:7000, may mimic unilat agenesis
ectopic kidney usually large & bilobed
Obstructive uropathy & VACTERL anomalies assoc

Pelvic Kidney - 1:1200, also mimic unilat agenesis
found adj to bladder or iliac wing, VACTERL anomalies assoc

Horseshoe Kidney - 1:400, fusion of upper poles at 7-9wks
rarely seen prenatally due to subtle appearance & N fxn
Malrotation & variable bridge of tissue only clue
3. Bladder Extrophy - 1:25,000, eversion & exteriorization
Cloacal extrophy is related but much rarer at 1:200,000
Debri in bladder indicates enterovesc fist
Patent urachus allows comm to ant abd wall
Urachal cyst - may resemble a distended or abn shaped bladder
does not fill and empty, observe for 60-90min to confirm

4. Urinary Tract Dilation - usually signifies obstruction
Renal pelvis AP diameter of <5mm normal, 5-9mm rarely sig
>10mm & rounded calyces - often progresses, need managment
Pelvis to Renal diameter of >50% a less sensitive finding
Bladder dil also usualy due to obs but can be w reflux
Urine Ascites - II' to decompression, impedes lung development

Urethral Obstruction - variable & can have insidious onset
Prox urethral & bladder dilation w wall thickening, "keyhole"
Bladder may have wall thickening or trabec w/o dilation
Oligo in 50%, less common to have calyectasis
Male - post urethral valves #1
Female - consider caudal regression, urethral atresia
Megacystis Intestinal Hypoperistalsis Syn also
Bladder or ureters may decompress via rupture - bad prognosis
indicates high Pres which often leads to renal dysplasia

UVJ Obstruction - Duplication is #1 cause, occur in 4% of pop
Upper moeity obstructs, lower moeity refluxes, surgery to fix
Dilated upper pole may displace lower pole inf & lat
Bilat ectopic ureterocele seen in 15%

UPJ Obstruction - #1 cause of neonatal hydronephrosis
30% bilat - Oligohydramnios usually, polyhydramnios poss
unilat can appear N on physical exam, may form giant cyst
can have oligo if contralat kid diseased w other process

Congenital Megaureter - dymotility of dist ureter
Fusiform dil of prox ureter
no obs, reflux or bladder dysfxn, NO therapy required
5. Renal Cysts - look for assoc anomalies esp if no obs present
Renal Dysplasia - results from anomalis diff of metaneph tiss
implies irreversible dysfxn, cortical cysts frequently
90% result from obstruction during nephrogenesis

Multicystic Dysplastic Kidney - II' to urteropelvic atresia
entire prox 1/3 of bud usually involved, no nephrons form
prox portion may be spared causing assoc hydronephrosis
collecting tubules dist randomly & become cystic, distorted
NO normal renal parenchyma exists
Contralat renal anomalies in 40%, 30% lethal w severe oligo
DDx - hydronephrosis, reniform contour & smooth unifrom calyx
Hydronephrosis & MCDK #1 causes of fetal abd masses

Obstructive Cystic Renal Dysplasia - obs in 1st half of gest
most common at urethral level, also at UPJ
Cysts confirm cortical renal dysplasia as early as 21wks
cysts may be smaller than US resolution, usually inc echogen
Hydronephrosis often present, appearance overlaps w MCDK
cysts tend to be relatively smaller, prognosis same

Infantile Polycystic Kidney Dz - Auto Rec, bilat medullary ectasia
innumerable 1-2mm cysts, nonobstructed tubules, Dx at 16wks
Can be severe w pulm hypoplasia resulting from oligo
Inc size w echogen cortex & echopenic medulla early
reverses appearance later in preg, maintain N shape
Infantile Type - die at birth, severe cystic kidneys, minimal liver
Juvenile Type - severe liver involvement, minimal renal dysfxn
DDx - bilat tumors, medullary sponge kid, nephroblastomatosis
medullary cytic Dz & congenital metabolic Diseases

Adult Polycystic Kidney Dz - auto dom, can be N thru 2nd tri
N amniotic fluid levels, echogenic & cystic kidneys
Chorionic villus sampling for Dx, 30% get liver Dz

Heredofamilial Cytic Dysplasias - assoc w renal cysts
Meckel-Gruber Syn - auto rec, bi nonobstructive cystic dysp
Occipital encephalocele, microcephaly & polydactyly
Jeune Syndrome - Asphyxiating Throacic Dystrophy, nonobs dysp
Ehlers-Danlos & Von Hippel-Lindau - freq renal cysts assoc
6. Renal Tumors - congenital rare
Mesobastic Nephroma - #1, solitary hamartoma w benign course
Freq assoc w polyhydramnios, but No need for preterm del
Nephrectomy curative, rare recurrance
US - solid protrusion w no defined capsule, sim Wilms
Wilm's - very rare in neonate

7. Fetal Gender - needed esp for assesment in genetic abn
ID of testis is scrotum is only way 100% prediction possible
can't be done before 28wks
30% have poor vis of perineum, esp before 24wks

8. Ovaries & Vagina - only seen if pathologically enlarged
Hydrometrocolpos - hypoechoic mass post to bladder
50% compress urinary tract & cause hydronephrosis
Ovarian Cysts - NO urinary compresion, Multiseptated
II' to maternal hormone, benign but assoc w hypothyroid
Small bowel obs or torsion poss, may require surg reduc
DDx - duplication (more tubular), mesenteric cyst
urachal cyst (extend to umbilicus)

Fetal anasarca, ascites, pericardial & plueral effusion

1. Immune Hydrops - initiated by maternal serum IgG to fetal RBC
sensitization occurs during previous fetal blood exposure
Rh (D) antigen causes 55%, 15% of whites neg, 8% of black
Before Rhogam it caused 98%, now more ABO & atypical antig
Hemolytic Anemia - caused by IgG crossing the placenta
relation between Hct & severity of hydrops not constant
Survival improves if no hydrops develops, esp P transfuse
Extramedullary Hematopoiesis - replaces N spleen & liver
Hepatospleenomegaly - early sign, Portal Venous Htn assoc
Umbilical venous htn causes palcental edema, >4cm abn
N hepatic protien production impaired
isolated severe hypoprotienemia not always assoc w hydrops
Cardiac Output increases due to anemia
Hypoxia & Acidosis occur, capillary dil & inc permeability
Anasarca - Generalized skin thickening >5mm, late manifest
Polyhydramnios - freq and early finding
Indirect Coombs Test - demonstrates presence of IgG Ab to RBC
Tx - Rhogam, Rh (D) immunoglobulin removes any fetal antigen
prevents recognition & IgG production
Amniocentesis if mother IgG pos
Bilirubin level infered by determining optical density
Severity level 1-3, Some obtain Hct for level 3
use cordocentesis, 2% mortality & inc sensitization
US Follow-up practical if no eff or skin edema evident
cordocentesis needed if level 3 & US evidence shown
Intrauterine transfusion may become necessary
Debate - deliver fetus when lung mature or at term?
term fetus better equiped to metabolize bilirubin

2. Nonimmune Hydrops Fetalis - Same Sx, no IgG, neg Coombs Test
Late manifestation of mult severe diseases
50% are cardiac arrythmia & structural anomalies
14% chromosomal esp triploidy, tri 18, 21 & Turners
Maternal Diabetes Mellitis & a-Thalasemia
30% uneventful during gest, No lab screens, US detects 100%
Polyhydramnios 75%, most common finding & reason for eval
Pulmonary hypoplasia freq results from plueral effusions
Placental thickening w anemia & cardiac anomalies, >4cm
Skin thickening >5mm more common when anemia NOT present
Cystic Hygroma - localized skin thickening, post neck
seen in 1/3 w nonimmune hydrops, abn lymphatic dev
Generalized Congenital lymphangictasia - always fatal
Prognosis - 50% overall, Arrythmia is most treatable cause
near 100% fatal when assoc w structural anomaly

Decidua from mother, chorion from fetus, approx 20 lobes
N mean thickness in mm equal to gest wks, not >4cm
variable, larger surface = smaller placenta & visaversa

1. Maturity - Graded 0-III based on calc pattern & indentions
0 - Smooth choionic face, no echogenic foci of calc
I - subtle indentions, randomly dispersed calc
II - clustering of comma like calc in basal layer
III - Lg irreg densities w post shadowing, deep indentions
assoc w lung maturity in 100% when seen over 38wks

2. Shape - Discoid echogenic mass, margin defined by vasc channels
Placenta Membranacea - thin layer covers entere uterine cav
Succenturiate - accessory lobe of placenta, inc Postpart risk
Circumvallate Placenta - Decidua basalis larger than placenta
raises & rolls edges of placenta

3. Placenta Previa - painless vaginal bleeding, usually at 3rd trimester
C-section required to prevent fatal hem
veins at edges can bleed even if only marginal previa
US - os must be visualized free of placenta to R/O
even if placenta appears clear, accessory lobe poss full
bladder may push placenta over os, empty or use vag
cervical os >3.5cm indicates compression, full bladder
Myometrial contraction can also contract & give false pos
Thicker than 1.5cm = contraction, repeat in 30min
72% are false positives in 2nd, 30% the reason not known
lower uterine seg lengthens more in 3rd, fewer false
15% assoc w placenta accreta, susceptable region to this

4. Placenta Accreta - abn adherance but no invasion of uterus wall
N decidua basalis not present for all or part of attachment
Inc in multiparous esp following C-section
difficult or impossible to extract placenta P delivery
Increta - invasion of myometrium, often requires hyterectomy
Percreta - penetration to serosa & adj organs esp bladder
5. Abruption - premature seperation of implanted placenta
assoc w pain & vaginal bleeding, <50% seen by US
can be retroplacental or marginal w subchorionic extention
Hematoma assoc - can also be intervillous, subamniotic
subchorionic over placenta or w/o extention under placenta
50% of placenta elevated or >60ml of blood = 75% mortality
Can present as diffuse placental thickening if isoechoic
DDx - infection or hydrops

6. Focal Placental Masses - seen in 10% of placentas
Subchorionic fibrin depositon, hematoma or cystic degeration
Not clinically significant even involving up to 50%
Chorioangioma - hemangioma of the placenta, in 1% on post exam
lg ones cause shunting, IUGR, hydrops, polyhydramnios, bleeding
often protrude from surface if large, solid & echogenic
Mets for breast or melanoma & placental teratoma poss, rare

7. Umbilical Cord - 54-60cm, <30cm = diff vag del, >100cm = knots
1-2cm diameter but can be N >3cm w excess Wharton's jelly
Two-vessel cord - single art in 1%, Inc at placental end
50% w assoc anomalies either severe or minor, 50% N
Vein Thrombosis - not always fatal if seen in N size cord
Hematoma - can be spontaneous or iatrogenic
Battledore Placenta - marginal insertion
Velamentous Insertion - vessels insert into attached meme
may cross cervical os, vasa previa can result in severe hem
Cysts - allantoic, amniotic inclusion or omphalomesenteric
rare assoc w omphalocele
Hemangioma - can be assoc w elev a-fetoprotien, hydrops, hem
Cord Prolapse - can be disasterous during delivery

1st tri - most from amniotic mem, electrolytes trans in
water then follows freely
Chorion Frondosum - site of free exchange w blood & amnion
Fetal skin - freely exchanges until keritinization at 24wks
Alveoli & GI tract continue thruout gest
25wks - fetal urine output 100ml/d, up to 600ml/d at term
like urine, it becomes increasingly hypotonic to serum
dec K+ & Na+ w inc urea & creatinine
N vol 60ml at 12wks, 200ml at 16wks, 900ml at term
post term vol dec to 500ml
Amniotic Fluid Index - 4 pockets measured in cm, one in each quadrant
vertical height of all 4 totaled, any total <5 is below normal
Dr. Terry sez Oligohydramnios only if NO fluid

Polyhydramnios - 60% idiopathic
Maternal Factors - diabetes & erythroblastosis fetalis
seen in 75% of hydropic fetuses
Placental Factors - Chorioangioma (hemangioma)
Fetal Anomaly - prox GI obs, neural tube defect, hydrops
#1 fetal cause of severe polyhydramnios is CNS abn

3% baseline risk for birth defects, chromosomes vs enviroment

1. Amniocentesis - done at 16wks, collects desquamated fetal cells
loss rate 0.5%, increases if attempted earlier
transversing placenta high risk, 25cc withdrawn
US does not decrease morbidity, does dec dry & bloody taps
Twins - inject indigo dye in 1st before going to 2nd
intracardiac air or KCl can selectively terminate bad twin

2. Chorionic Villus Sampling - Can be done earlier, 10-12wks gest
transcervical or transabdominal approach, US guidance needed
technically much more difficult than amnio
loss rate is 0.8% greater than 16wk amniocentesis

3. Rhesus Sensitization - slight increased risk following amnio
giving Rh immune globulin after procedure controversial

4. Fetal Blood Sampling - 48hrs for analysis vs 3wks for amnio
Fetoscope guidance risk 5% vs US guidance risk of 1%
Fetal Tissue can also be obtained in select med centers
Need for less DNA by modern techniques may eliminate this

5. A-Fetoprotein Screening - glycoprotein from fetal liver
normally much higher in fetal serum than amniotic fluid
3 mil ng/ml - 20,000 ng/ml - 30 ng/ml in maternal serum
1 in 15 fetuses abn, levels <.4 or >2.5 MOM (mult of med)
Neural tube defects cause loss of integument, inc AFP
tends to have regional & familial predominance
Teratomas, Cytic Hygromas & abd wall defects also inc AFP
Tisomy 21 causes abnormally LOW AFP in maternal serum
B-hCG & maternal serum estriol levels also altered
False postive rate high, misdating & mult preg for example
Level 3 Ultrasound - targeted to pts w abn AFP to find abn
Encephalocele - check mult transverse sections of skull
spina bifida - look for Chiari II & effaced cisterna magna
careful examination of the spine longitudinal & trans
Omphalocele & gastroschisis - look for N cord insertion
Facial & postpharyngeal Teratomas & Cystic Hygromas
Meckel Syndrome - cystic dysplastic kidneys, polydactly
encephalocele & microcephaly

PATTERNS OF MALFORMATION WITH CHROMOSOMAL ABN

1. Trisomy 21 - dysmorphic features not seen by US in 50%
Nuchal Skin Folds - redundant & thickened in 80%
direct at suboccipital-bregmatic trans axial plane
skull to outer skin >6mm abn at 15-20wks
Femur & Humerus Length - below .92 standard dev at 15-20wks
Heart Defects - 20% die in 1st year due to heart failure & luekemia
VSD, ECD & ostium primum ASD freq
Duodenal Atresia - 10%, 30% of babies w "double bubble"
Hydrops - freq in 2nd trimester as w all cytogenetic disorders
widely spaced 1st & 2nd toes

2. Trisomy 13 - Patau Syn, profound MR, only 18% survive 1st year
CNS disorders - holoprosenceph #1, agenesis of CC also
Craniofacial disorders - micrognathia, cleft, sloped forehead
Congen heart defects - Dextrocardia, VSD & ASD
2nd tri IUGR, polyhydramnios, hypotonia, GI & renal abn also
all cases of Omphalocele should be Karyotyped

3. Trisomy 18 - Edward Syn, similar presentation to Patau syn
Limb malformations also included - clubfoot, clenched hand
Micrognathia, dolichocephaly & prom occiput characteristic
Choroid Plexus cyst also common, often large & bilat

4. Turner Syndrome - missing X chrom, most miscarry 1st or 2nd tri
Corarctation of aorta accounts for 70% of deaths
R vent enlarged due to shunting across ductus to dist aorta
Cystic Hygromas, Nuchal Edema & freq Hydrops

5. Triploidy Syndrome - 2 sperm fertilize egg, 20% of miscarriages
live birth rare, severe IUGR, disproportionate Lg head
mult system & amnion abn