Test3:Review Flashcards
What structure carries oxygenated blood from the umbilical vein to the IVC?
the veins carry oxygenated blood
the arteries carry deoxygenated blood
what is the term that indicates the fetal head is towards the fundus of the uterus?
breech
what are the three vessels found in the umbilical cord?
one vein
two arteries
which vessel shunts the blood away from the fetal lungs?
ductus areteriosus
What is the 4 quadrant fluid assessment?
AFI
What is MVP?
maximum vertical pocket
What is the test to perform fetal well being?
biophysical
what is a normal AFI?
5-20cm
What are the numbers that indicate oligohydramnios and polyhydramnios?
MVP:
oligo- <2cm
poly- >8cm
AFI:
oligo- <2cm
poly- >24cm
what measurement do we use for cord Doppler?
25-29wks: 4.0
29-34wks: 3.3
34-40wks: 3.0
what is a false knot of the umbilical cord?
blood vessels are longer than the cord, folded on themselves
what is a true knot?
actual knot, may be single or multiple, may be formed when a loop of cord is slipped over the infant’s head or shoulders
what are fetal membranes comprised of?
chorion
amnion
allantois
yolk sac
chorion
originate from trophoblastic cells and remains in contact with trophoblasts throughout preg
amnion
develops at 28th menstrual day, is attached to margins of embryonic disk
allantois
tubular extension of the endoderm of the yolk sac, becomes umbilical vessels
yolk sac
circular structure seen between 4-10wks gest, supplies nutrition
what is the decidual basalis?
decidual reaction that occurs between the blastocyst and the myometrium
what is the decidua capsularis?
reaction occuring over blastocyst closest to endometrial cavity
what is the decidua vera (parietalis)?
reaction except for areas beneath and above implanted
what is the maternal side of the placenta? fetal side?
maternal-basal plate
fetal- chorionic plate
major functions of the placenta:
respiration
nutrition
excretion
protection
storage
hormonal production
respiration
transfer of oxygen from maternal blood across the placental membrane into fetal blood is by diffusion
the placenta acts as fetal lungs
nutrition
water, inorganic slats, carbohydrates, fats, proteins, and vitamins pass from maternal blood through the placental membrane into fetal blood
excretion
waste products cross membranes from fetal blood and enter maternal blood
excreted by mother’s kidneys
protection
some microorganisms cross the placental border
storage
carbohydrates, proteins, calcium, and iron are stored in placenta and released into fetal circulation
hormonal production
produced by syncytiotrophoblast of placenta: human chorionic gondatropin (hcg), estrogens, progesterone
what is a velamentous placenta?
umbilical cord insertion on the surface of the placenta in the membranes
what is a battledore insertion?
the insertion of the umbilical cord at the margin of the placenta within 10mm of the edge
what is a marginal or an accentric insertion of the placenta?
battledore insertion
what is the primary cause of placentomegaly?
placentomegaly- placenta weighing more than 600g
primary cause-diabetes
what are percreta, accrete, increta? which is worse?
placenta accrete- superficially to myometrium; mild
placenta increta- deep into myometrium; moderate
placenta percreta- through the myometrium; severe
what is an accessory lobe of the placenta?
succenturiate placenta; occurs in 3-6% of pregnancies
what is a low pressure bleed of the placenta?
marginal
what is marginal?
most common type and is a sub chorionic bleed
(low pressure bleed)
what is partial?
just about to cover the cervical os, but doesn’t cover it all the way
what is a previa?
implantation of the placenta over the internal cervical os
what maternal abnormalities demonstrate a small placenta?
intrauterine growth restriction
intrauterine infection
aneuploidy
what maternal abnormalities demonstrate a large placenta?
maternal diabetes
maternal anemia
x-Thalassemia
Rh sensitivity
Fetomaternal hemorrhage
Chronic intrauterine infections
Twin-twin transfusion syndrome
congenital neoplasms
fetal malformations
what is vasa previa?
placenta covering the cervix, cord insertion at cervix
what is circumvallate placenta?
condition where the chorionic plate is smaller than the basal plate, the margin is raised with a rolled edge
what is circummarginate placenta?
chorionic place of the placenta is smaller than the basal plate, with a flas interface between the fetal membrane and the placenta
what is the chorion frondosum?
portion of chorion that develops into fetal portion of placenta; site where water exchanged freely between fetal blood and AF across amnion
Amniotic Band Syndrome
associated with abnormality in fetal membranes; common, non-recurrent cause of various fetal malformations involving limbs, craniofacial region, trunk
Amniotic sheets, shelves, or folds
identified as echogenic, nonfloating bands crossing through amniotic cavity, do not cause fetal malformations, most likely signify uterine synechiae
what regulates the amount of amniotic fluid?
AF volume increases rapidly during 1rst trimester
fetus swallows fluid, reabsorbed by GI tract, recirculates through kidneys
increased AF production in 1rst trimester
by 20wks gest, AF volume increases by 10ml/day
fluid produced by fetal urination slightly exceeds amount removed by fetal swallowing
conditions associated with polyhydramnios
central nervous system (CNS) disorders
gastrointestinal (GI) problems
CNS disorders cause depressed swallowing
GI abnormalities result in ineffective swallowing that are often caused by a blockage (atresia) of the esophagus, stomach, duodenum, or small bowel
conditions associated with oligohydramnios
congenital anomalies
IUGR
post term preg
rupture of membranes (ROM)
iatrogenesis
hypertension
preeclampsia
chronic cardiac disease
connective tissue disorders
patients receiving indomethacin
functions of the amniotic fluid
allows fetus to move freely within amniotic cavity
maintains intrauterine temperature
protects developing fetus from injury
when is the amniotic fluid at its greatest?
18-20wks gest
what is the cause of a patient having persistant polyhydramnios?
diabetes
how do sonographers typically evaluate AF?
eyeball assessment
what is the debris in the AF?
vernix caseosa particulate matter
intra-amniotic blood
intra uterine meconium passage
oligohydramnios could be attributed to:
congenital abnormalities
IUGR
post term preg (42wks)
rupture of membranes (ROM or PROM)
chorionic villus sampling
Iatrogenesis
polyhydramnios (hydramnios) volume
> 2,000 ml
hydrops
disparity between amounts of serous fluid being produced and absorbed
hydrops indications:
pleural effusions
ascites
cardiac effusion
skin edema
anasarca
hydrops fetal findings:
enlarged umbilical cord
polyhydramnios
placental edema
enlarged liver and spleen
in many cases, highly associated with mortality
Immune hydrops
associated with alloimmune hemolytic disease (erythroblastosis fetalis) or rhesus (Rh) isoimmunization
maternal blood sampling and history of previously affected fetus extremely important for preg management
nonimmune hydrops
presence of abnormal accumulations of fluid in fetal body and/or skin
is associated with numerous conditions and causes
nonimmune hydrops causes
may be sporadic condition or associated with numerous other causes
cardiac insufficiency one of the most common causes
cardiac insuffiency can result from cardiac anomalies (tumors) or arrhythmias (tachycardia)
placenta infarcts
focal, discrete lesion caused by ischemic necrosis
common, about 25% of preg, usually small with no clinical significance
large infarcts may reflect underlying maternal vascular disease
acute, subacute, and chronic stages
majority hyperechoic in acute stage, ultrasound may be unable to distinguish them from intraplacental hemorrhages
calcification may occur over time
placentomegaly-how many grams does placenta weigh?
600g
ductus venosus
connects the umbilical vein to the IVC and allows oxygenated blood to bypass the liver and return directly to the heart
ductus arteriosis
communicating structure that carries oxygenated blood from the pulmonary artery to the descending aorta, closes after birth
