side dishes Flashcards
what does the placenta do
transports nutrients and oxygen to fetus
removes waste from fetus
produces hormones to sustain pregnancy
forms barrier between mat and fetal blood
placental is fully formed by __ GA
16-18w
fetal trophoblast becomes __
chorionic villi (frondosum)
maternal decidua becomes __
decidua basalis
placenta made up of __ cotyldons divided by septa
15-20
chorionic plate vs. basal plate
chorionic = fetal side
basal = maternal
grade 3 placenta prior to 36w GA is associated with __
advanced IUGR
sig mat HTN
heavy smoking
normal mean placental thickness roughly equal to __
weeks GA
> 4cm abnormal
- measure from chorionic to basal plate
thick HETEROGENEOUS placenta associated with __
tirploidy
molar pregnancy
placental hemorrhage
fetal viral infections (oft with calcs)
thick, HOMOGENEOUS placenta associated with __
gestational DM
fetal hydrops
fetal viral infections (with calcs)
mat anemia
aneuploidy
thin placenta associated with __
mat HTN
chromosomal abnormalities
polyhydramnios
severe IUGR
advanced DM preconception
severe intrauterine infection
placenta membranacea
most hypoechoic lesions within placenta are __
venous lakes
** maternal blood
rouleau
placental lake aka
sonolucencies
hole
lucencies
** not lacunae??
most common placental tumour
choriocarcinoma
- benign
sono features of choriocarcinoma
solid mass with variable echo pattern bulging at fetal surface (chorionic) of placenta
variable doppler (sometimes avascular)
+/- polyhydramnios
fetus normal or signs of hydrops
*** large >5cm associated with fetal CHF, IUGR and nonimmune hydrops
which placental tumour may elevate MSAFP
choriocarcinoma
a placenta which partially or completely covers the internal os of the cervix; degrees
placenta previa
complete
partial
marginal
low lying <2cm
placental migration aka
dynamic placentation
TROPHOTROPISM
normal migration from internal OS with progression of pregnancy
“grows toward nourishment” at fundus of uterus (better blood supply)
a normally implanted placenta that prematurely separates from the uterine wall
abruptio placenta
- mild to severe
clinical signs of placental abruption
mild tenderness to rigidity
+/- bleeding
elevated MSAFP
risks for abruptio placenta
mat HTN
PROM
short umb cord
advanced mat age
previous abruption
abdominal trauma
smoking/cocaine
retroplacental myoma
fetal complications associated with abruptio placenta
fetal hypoxia
IUGR
premature delivery
demise
maternal complications of abruptio placenta
hypovolemic shock/cardiac arrest
* state of decreased blood volume
acute renal failure
disseminated intravascular coagulopathy
* excessive clotting throughout body
type of abruptio placenta
retroplacental
marginal
‘sono features of abruptio placenta
hematoma appearance either retroplacental or subchorionic
may appear normal if blod is freely escaping the uterus
* could be bleeding in a way that is not detectable
placenta accreta spectrum aka
placenta creta
placental invasion
morbidly adherent placenta (MAP)
accreta, increta, percreta
deficiency of decidua basalis
underdeveloped dicidua basalis allows varying degrees of invasion of chorionic villi into myometrium
replaced with connective tissue
accreta, increta, percreta
chorionic villi attach to the myometrium; most common form of placental invasion
placenta accreta
chorionic villi extend INTO the myometrium
placenta increta
chorionic villi penetrate THROUGH the uterine wall (ie into bladder)
placenta percreta
“past”
risk factors for placental invasion
previous csec
anterior placental previa/ low lying
hx of ut sx
increased parity
elevated MSAFP
sono findings for placental invasion in 1st trimester
may see GS location in csec scar
multiple irregular vascular spaces within placenta
colour usually intense blood flow within anechoic placental space (due to direct association with ut arteries)
sono features of placental invasion in 2nd/3rd trimester
multiple vascular lacunae
loss of normal hypoechoic retroplacental zone
* check angle of probe; can be angle dependent
** retroplacental myometrium should be >1mm
**pitfall, retroplacental zone may not be seen with normal anterior placenta (false positive)
extensive villi into myometrium, serosa, or baldder
abnormal uterine serosa-bladder interface
secondary placental lobe(s) attached to main body by velamentous connection
succenturiate lobe
significant associated risks for succenturiate lobe(s)
antepartum bleeding
vasa or placenta previa
fetal distress due to trauma to interconnecting vessels
postpartum bleed (retention)
succenturiate variant where two similarly sized placental lobes are present with vascular connection
bilobed placenta
ddx FMC, SCH
smooth chorion insertion into chorionic plate closer to the centre of the placenta than at the margin resulting in chorionic plate being smaller than basal plate
extrachorial placenta
partial (asymptomatic) or
complete (entire edge of placenta)
* associated with antepartum bleeding, preterm labour, placental abruption and IUGR
- circumvallate
- circummarginate
smooth chorion inserts closer to the centre of placenta and rolls UP
circumvallate placenta
ddx synechiae, ut septum, amniotic band syndrome
smooth chorion inserts closer to the centre of placenta and often not seen with ultrasound
circummarginate placenta
flat interface
‘spread like margerine’
LAX, circumvallate placental edges appear __ and SAX the edges appear __
LAX -> long
SAX -> short
a thin, membranous placenta occupying the entire periphery of the chorion (covering most or entire uterine wall)
placenta membranacea
decidua capsularis did not flattern the chorionic villi
placenta usually thinner than normal
placenta membranacea associated with __
invasion and placenta/vasa previa
CI at edge of placenta
battledore insertion
Ci away from placenta into membranes
velamentous CI
cylindrical shaped placenta (ring)
annularis placenta
thinning/ hole in middle of placental tissue
fenestrata placenta
embryonic diverticulum from YS to body stalk that becomes blind-ended tube from bladder to umb cord in fetus
allantois
-> urachus
-> median umbilical ligament
embryonic connection from midgut to YS that narrows and disappears by 9w GA
vitelline duct
-> Meckel diverticulum if not obliterated in utero (slight bulge in small intestine)
umb vein brings blood __ fetus and the umbilical arteries __ the fetus
vein TO the fetus
arteries RETURN to placenta
arteries are protected and insulated by __
Wharton’s jelly
covered by amnion
normal cord length full term
55cm, 1-3cm thick
short umb cord associated with
fetal movement disorders
placental abruption
cord rupture (subsequent demise)
long umb cord associated with
fetal entanglement
true knots
thrombi
normal umb coiling index (UCI)
~0.44 coils/ cm
hypercoiled umb cord associated with
increased incidence of premature delivery
occlusion in cases with entanglement
low arterial pH
asphyxia
**usually associated with cocaine withdrawal issues
undercoiled umb cord associated with
kinking, compression
low APGAR score
associated risks if 2VC not an isolated finding
fetal anomalies (cardiac, renal)
IUGR
aneuploidy
velamentous CI
preterm delivery
eccentric CI __ cm from edge
> 2cm but still off centre
marginal insertion __ cm from edge
<2cm
can progress to velamentous Co and vasa previa
associated risks with velamentous CI
no wharton’s jelly (vessel compression)
vasa previa
hemorrhage
associated findings with velamentous CI
esophageal atresia
VSD
2VC
succenturiate placenta
low brith weight, cleft palate, hip dislocation/dysplasia, asymmetrical head shape, spina bifida
pulse of velamentous CI will match __ heart rate
fetal
confirms not maternal vessels
common umb cord masses
cysts
neoplasm
knots
- false (kink)
- true (polyydramnios, increased risks fetal loss)
hematoma
focal edema
t/f single loop of cord around fetal neck is not cause for concern
true
if many, can cause cord shortening and the associated risks of that
asphyxia
management is close surveillance (count fetal movement, etc)
PROM with cord prolapse; look for __
extent
= ruptured membranes and can restrict or occlude blood flow to fetus (compression)
***** obs emergency
causes for cord prolapse
abnormal presentation of fetus
LONG cord
polyhydramnios
prematurity
twins
***** obs emergency
cord wrapped around neck aka
nuchal cord
causes for cord compression
oligohydramnios
nuchal cord loops
true knots
compression by fetus (ie. prolapsed cord, undercoiled cord)
SHORT cord
what are the pregnancy membranes
amnion and chorion
amniochorionic membrane
wall preventing fluid from leaving too early “impermeable to amniotic fluid”
__ membrane develops from trophoblast and is surrounding blasocyst
chorion
outer blastocyst divides into 2 layers of trophoblast; they are __
syncytiotrophoblast (outer)
** future placenta
- dissolves endo to fuse to what is now decidua basalic
cytotrophoblast (inner)
** future smooth chorion
- decidua capsularis
__ membrane forms adj to embryonic disc within blastocyst
amnion
as gest sac explands, __ contacts decidua parietalis and fuses during 2nd trimester
amnion
when amnion fuses to decidua parietalis, the uterine cavity is __
obliterated
shelf vs sheet vs strand
shelf = indenting synechiae, circumvallate placenta, ut septum
sheet = compartments
** line no matter how you rotate
strand = linear membrane cause for amniotic band syndrome; sticky when rupture early
** dot when you rotate
fetal development outside of amniotic cavity secondary to late rupture of amnion
extra-amniotic pregnancy
associated with SHEET septation
septation sheets can be normal if separation occurs __ GA
< 16w GA
amniochorionic membrane lifting from ut wall by subchorionic hematoma
abnormal septation sheet
can cause compartments and issues
which membranous septation drapes over an anatomic ridge (ie. synechiae)
amniochorionic shelf
vascularity of septations
avascular
some SHELVES have vascularity depending on type of anatomical adhesion (ie. uterine septation)
amnion abuts the chorion around __ GA and amnion fuses with chorion around __ GA
abuts at 12-16w GA
fuses 20w GA
chorionic cavity between amnion and chorion
subamniotic space
- not continuous with uterine cavity
uterine cavity between chorionic membrane and uterine wall
subchorionic
*fluid can leak to cervical cavity
potential spaces for blood collection
subchorionic (uterine cavity)
retroplacental
subamniotic (chorionic cavity)
amniotic cavity
subchorionic hemorrhage aka
subchorionic hematoma
subchorionic bleeds aka
marginal placental abruption
*premature detachment at edge of placenta
separation of amnion and chorion membranes
amniochorionic separation
*primary and secondary
who regulates the amniotic fluid
fetus is the regulatory apparatus
__ produces amniotic fluid
chorion plate of placenta
skin
urinary tract
respiratory tract
__ removes amniotic fluid
GI tract
respiratory tract
uterine wall
__ are the primary source of amniotic fluid after 16w GA
kidneys
amniotic fluid peaks at __ GA and drastically reduces after __ GA
peaks at 30-36w
decreases after 42w
SDP
2-8 cm
AFI
10-20 cm
- MB 8-18 cm
fetal causes for oligohydramnios
triploidy
kidney problems
bladder outlet obstruction
maternal causes for oligohydramnios
PROM
IUGR (shit placenta, HTN, drugs)
placental causes for oligohydramnios
insufficiency
twin to twin transfusion syndrome (DA)
** donor twin has IUGR
recipient hydrops
fetal complications with oligohydramnios
pulmonary hypoplasia
* bell shaped chest
distress (cord compression; asphyxia)
clubfoot
dolichocephaly
management of oligohydramnios
amnioinfusion
* injection of saline
most common cause for polyhydramnios
idiopathic
fetal causes for polyhydramnios
CNS lesion
open NTD
upper GI atresias or bowel obstruction
dandy walker malformation
shit lungs, esophageal compression
CHF
skeletal dysplasia
unilat renal agenesis
expected AFI with unilat renal agenesis
polyhydramnios
- paradoxical increase of amniotic fluid
expected AFI with upper GI atresia
polyhydramnios
maternal causes for polyhydramnios
DM
hydrops (immune and non immune)
expected AFI with mat DM
polyhydramnios
expected AFI with mat HTN
oligohydramnios
** fetal IUGR
expected AFI with dandy walker malformation
polyhydramnios
placental causes for polyhydramnios
twin to twin transfusion
** recipient twin hydropic with polyhydramnios
can be MCDA (stuck twin gets oligo, other twin poly)
large placental chorioangioma
- fluid overload and fetal CHF
features of placenta with polyhydramnios
thin placenta in severe cases
+/- cervical incompetence
severe polyhydramnios SDP and AFI
> 16 cm
AFI >/= 35 cm
management severe polyhydramnios
therapeutic amniocentesis
indomethacin therapy
maternal clinical presentation with severe polyhydramnios
overdistended ut resultant preterm labour
SOB
insomnia
leg edema
supine hypotensive syndrome
physiological sources of amniotic fluid echoes
desquamated fetal cells (epithelial)
venix caseosa (covering on fetal skin)
meconium (poop?)
sludge in amniotic fluid risk for __
PROM and chorioamnionitis
cervix length
> 3cm TAS
2.5cm EVS
cause for congenital incompetence of cervix
DES exposure
isolated idiopathic
connective tissue disorder
** ie rheumatoid arthritis, lupus, sclerosis
progressive severity of cervical incompetence
T
Y
V
U
what GA is it okay to perform cervical stress test
15-24w GA
most common suture technique for cervical cerclage
McDonald ‘purse stringe’
preterm is __ GA
<37w
post dates is __ GA
> 42w
fetal vessels crossing IO, situating between presenting part of fetus and cervix
vasa previa
partial separation (opening) of myometrium at the location of uterine scar (ie csec)
uterine dehiscence
*risk of rupture
what length of uterine dehiscence is considered at risk of rupture
<3mm AP
