Ch. 17 The Placenta and Umbilical Cord Flashcards
which side of the placenta is rough and irregular in nature
The maternal surface
The fetal surface of the placenta is smooth and covered by which membranes
chorionic and amniotic
List functions of the placenta
Secretion of progesterone
secretion of hCG
exchange of oxygen, waste products and nutrients between the fetus and mother
What is the fetal side of the placenta called
Decidua frondosum
What is the maternal side of the placenta called
Decidua basalis
Each functional unit of the placenta is known as a
Cotyledon (12-20 per placenta)
Describe the placental grades
Grade 0 - up to aprox 28-31 weeks, no calcs, smooth chorionic surface
Grade 1 - up to aprox 31-36 weeks, scattered calcs, slight contouring of chorionic surface
Grade 2 - up to aprox 36-38 weeks, basal layer calcs
Grade 3 - 38+ weeks, basal calcs, interlobar septal calcs (cotyledon formations), infarcts
Type of placenta that is characterized by a small central chorionic ring surrounded by thickened amnion and chorion. May predispose to abruption, ante bleeding, threatened ab
Circumvallate placenta
Type of placenta with a central attachment of the membrane without a central ring
Circummarginate placenta
An accessory lobe with vascular connections to the main placenta
Succenturiate placenta
Placenta divided into two lobes but united by primary vessels and membranes
Bilobed/ bipartite placenta
A ring shaped placenta
Annular placenta
Placenta thickness is usually less than
5 cm AP
List some causes of an increased placental thickness
GDM
maternal infection
chorioangioma
multiple gestation
maternal anemia
hydrops fetalis
sacrococcygeal teratoma
partial mole
chromosomal abnormalities
abruption (appears thick due to retroplacental clot)
List causes of a decreased placental thickness
Preeclampsia
IUGR
PGDM
Intrauterine infection
Poly (it appears thinner)
What measurement is considered a decreased placental thickness
<1.5 cm
List causes that may predispose a patient to placenta previa
Multiparous women
previous C-section
myomectomy
Multiple D&C causing uterine scarring
Most common symptom of placenta previa
Painless vaginal bleeding
Not a type of previa in which the placenta is within 2 cm from the internal os
Low lying placenta
Premature separation of all or part of a normally implanted placenta from the myometrium
Placental abruption
List predisposing conditions or factors of placental abruption
Maternal hypertension
AMA
mulitparity
maternal vascular disease
cigarette smoking
trauma
cocaine use
leiomyomas
Symptoms of placental abruption
ABD PAIN with or without BLEEDING
What are the two types of placental abruption?
Describe each
Concealed - hemorrhage is confined to the uterine cavity, detachment may be complete and consequences are severe, may be seen on US
External - blood drains through the cervical os. can be difficult to see on US if there is no more blood in retroplacental space
Sono finds of placental abruption
evaluation of the plac from the uterine wall
retroplacental fluid collection of varying echogenicity (depending on age)
normal or thickened appearing plac
Chorionic villi penetrate/perforate the myometrium
Placenta percreta
Chorionic villi are in direct contact with the myometrium but do NOT invade
Placenta accreta
Chorionic villi invade the myometrium
Placenta increta
Sono finds of placenta accreta/percreta/increta
loss of normal hypoechoic retroplacental clear zone
excessive lacunae
hypervascularity
What are placental lakes
pools of maternal venous blood within the placenta
Pooling of maternal blood in the subchorionic space
Fibrin deposition
Caused by fetal bleeding into the intervillous space with an increased incidence with associated Rh incompatibility
Intervillous thrombosis
T or F, placental infarcts will demonstrate color flow with both color and power doppler
F, infarcts will have NO blood flow
An accumulation of blood beneath the chorion
Subchorionic hematoma aka submembranous hematoma
Vascular tumor of the placental tissue that is rare
Chorioangioma
Large chorioangiomas (>5cm) may cause complications such as
Poly, fetal hydrops, it is associated with increased MS-AFP
Sono finds of chorioangiomas
Solid well circumscribed plac mass, possibly near PCI
What surrounds the umbilical cord
Whartons jelly and amnion
The most commonly encountered umbilical cord abnormality
Two vessel cord aka bivascular cord - can be caused by primary agenesis or atrophy
Anomalies associated with 2VC
GU anomalies
trisomy 13 and 18
cardiovascular anomalies (why Dr Bruner orders echo)
CNS anomalies
omphalocele
Type of umbilical cord cyst that is a remnant of a duct and is located away from the fetus
Allantoic duct cyst
An umbilical cord cyst that is located close to the fetus and contains remnants of GI tissue
omphalomesenteric duct cyst
Emergent situation in which the umbilical cord protrudes through the cervix or adj to fetal presenting part
Cord prolapse
Fetal vessels crossing the cervical internal os, passing between the cx and presenting part with the membranes intact
vasa previa
Vasa previa is commonly associated with what placental anomaly
Velamentous insertion
Umbilical vein thrombosis may occur in what cases
after intrauterine transfusion
during fetal blood sampling
diabetic mothers
non-immune hydrops
Sono finds of umbilical vein thrombosis
increased echogenicity in the lumen of umbilical vessels
absence of color and spectral doppler
True umbilical cord knots are rare, they occur mostly in what cases
Mono mono twins
Attachment of the cord at the periphery of the placenta, the cord enters directly into the edge of the plac
Marginal / Battledore insertion
Attachment of the cord to the membranes rather than to the placental mass.
Velamentous cord insertion
Velamentous cord insertions may be associated with what fetal complications
IUGR
preterm birth
congenital anomalies
