Fetal Environment & Maternal Complications
Clinical findings of placental abruption:
1. Abdominal pain (often sudden onset) 2. Possible vaginal bleeding 3. Uterine contractions 4. Uterine tenderness
What are the 3 parts of the placenta?
1. Chorionic plate 2. Placental substance 3. Basal layer or Basal plate
Sonofindings of placental abruption:
1. Hematoma located either at the edge of the placenta or between the placenta and the myometrium
Sonofindings of Vasa previa:
1. Identification of vessels over the internal os of the cervix with the use of Color Doppler 2. Velamentous cord insertion
Sonofindings of uterine synechia(e):
1. Linear, echogenic band of tissue transversing the uterine cavity 2. The band does not involve fetal parts, & the normal fetus appears to move freely
Sonofindings of placenta accreta, increta, percreta:
1. Placenta previa (frequent associated finding) 2. Loss of the normal hypoechoic interface
Clinical findings of chorioangioma:
1. Possible elevation in maternal serum alpha- fetaprotein
Clinical findings of Placenta previa:
1. Previous C-section or uterine surgery 2. Painless vaginal bleeding 3. Possibly asymptomatic
Clinical findings of placenta accreta, increta, percreta:
1. Previous C-section or uterine surgery 2. Painless vaginal bleeding if placenta previa 3. Possibly asymptomatic
Sonofindings of chorioangioma:
1. Well-circumscribed solid hypoechoic or hyperechoic mass within the placenta
When will a definite placenta be identified sonographically?
10-12 weeks
The placenta consist of how many cotyledons?
10-30
The thickness of the placenta should not exceed how many cm?
4 cm
How much does the placenta normally weigh and what's its diameter?
450-550 grams Diameter is 16 to 20 cm
Possible causes for thick placenta:
Diabetes mellitus Maternal anemia Infection Fetal hydrops Rh isoimmunization Multiple gestations
Possible causes for thin placenta:
Diabetes mellitus (long standing) Intrauterine growth restriction Placental insufficiency Polyhydramnios Preeclampsia Small-for-dates fetus
Which is the most common placental hemorrhage identified with sonography?
Marginal abruption
Sonographic appearance of Grade II placenta:
Moderate indentations in the chorionic plate with "comma-like" calcifications in the placental substance
Marginal placenta previa sono appearance:
Placenta lies at the edges of the internal os
A condition that is defined as the abnormal adherence of the placenta to the myometrium in the area where the decidua is either absent or minimal is termed?
Placental accreta
Low-lying placenta previa sono appearance:
Placental egde extends into the lower uterine segment but ends more than 2 cm away from the internal os
Partial placenta previa sono appearance:
Placental partially covers the internal os
Sonographic appearance of Grade III placenta:
Prominent indentations in the chorionic plate that extends to the basal layer with diffuse echogenic and anechoic areas noted within the placental substance
Sonographic appearance of Grade I placenta:
Subtle indentations on the chorionic plate, with some small calcifications within the placental substance
Sonographic appearance of Grade 0 placenta:
Uninterrupted chorionic plate and homogeneous placental substance
The vessels of the umbilical cord are surrounded by a gelatinous material called?
Wharton jelly all of which is covered by a single layer of amnion
Succenturiate lobe are?
additional smaller lobes located separate from the main segment of the placenta
Placenta accreta is when there is:
adherence of the placenta to the myometrium
What is the most common location for an chorioangioma?
adjacent to the umbilical cord insertion site at the placenta
The placenta should be evaluated for placenta previa after 20 weeks with:
an empty maternal bladder using a trans abdominal approach, because the fully distended bladder may lead to a false-positive dx of the placenta previa
How do venous lakes appear sonographically?
anechoic or hypoechoic areas & may contain swirling blood
Where is the placental substance located?
between the chorionic plate and the basal layer
What type of placenta consists of 2 separate discs pf equal size?
bilobed placenta
The placenta is derived from:
both fetal & maternal cells
What is the preferred method of delivery when a placenta previa is present?
c-section because both fetus & mother have increased risk of death
What may be seen in the placenta with advancing gestation?
calcifications and indentations within the basal and chorionic plates
What is the most common placental tumor?
chorioangioma
What is the fetal contribution of the placenta?
chorion frondosum (derived from blastocyst & containing the chorionic villi )
An abnormally shaped placenta caused by the membranes inserting inward from the edge of the placenta, producing a curled up placental contour is termed?
circumvallate placenta
Placental abruption can be further described as:
complete partial marginal
The placenta has groups or lobes of chorionic villi which are termed?
cotyledons
What is the maternal contribution of the placenta?
decidua basalis (the endometrium beneath the developing placenta)
As a result of the abnormal adherence of the placenta, the placenta does not ______ at birth.
detach
How does a placenta appear sonographically?
echogenic thickening surrounding part of the gestational sac
Where can a retroplacental hematoma be located?
either between the placenta and myometrium or under the chorionic membrane
In later pregnancy the placenta also produces:
estrogen and progesterone taking over the function of the corpus luteum
In vasa previa, if the vessels rupture, it will then lead to:
exsanguination of the fetus
What maintains the corpus luteum of the ovary?
hCG
Depending on the amount of invasion or penetrations of the placenta into the myometrium, the patient could suffer from:
heavy bleeding at delivery & possible uterine rupture
A complete abruption is the most severe, often results in the development of a:
hematoma, which is located between the placenta and the myometrium
What are maternal conditions that are linked to the development of placental abruption include:
hypertension, preeclampsia, cocaine use, cigarette smoking, poor nutrition, & trauma
What are the 3 different terms associated with placental accreta:
i.placental accreta ii.placental increta iii.placental percreta
When is placenta previa discovered more often in women with history of?
in women with history of multiparty, advanced maternal age, previous abortion, & prior cesarean section
Uterine synechiae are a result of:
intruterine adhesions, as seen with Asherman syndrome, that result from uterine surgery
Increta and percreta can be dx based on the amount of:
invasion & if there is a breach of the serosal layer of the UT
Placenta increta is when there is:
invasion of the placenta within the myometrium
What is the basal layer of the placenta?
is the area adjacent to the uterus
Sonographic appearance of placenta increta:
loss of normal hypoechoic interface between the placenta and myometrium with invasion into the myometrium
Sonographic appearance of placenta percreta:
loss of normal hypoechoic interface between the placenta and myometrium with penetration beyond the serosa
Sonographic appearance of placenta accreta:
loss of normal hypoechoic interface between the placenta and the myometrium
Both a thin & thick placenta are associated with:
maternal and/or fetal abnormalities
What else could cause a false-positive placenta previa?
painless myometrium contractions that occur in the lower uterine segment (they resolve as sonography continues)
Placenta previa is a common cause of ___________ _________ in the 2nd & 3rd trimesters.
painless vaginal bleeding
Placenta percreta is when there is:
penetration of the placenta through the serosa and possible into adjacent organs
Marginal abruptions lies at the edge of the ____________.
placenta
What is a vital organ to the fetus during pregnancy?
placenta
What produces hCG?
placenta
Complete(total) placenta previa sono appearance:
placenta covers the internal os completely
When implantation of the placenta occurs within the lower uterine segment it leads to:
placenta previa
Premature separation of placenta from the uterine wall before birth of the fetus, thus causing hemorrhage is termed?
placental abruption (abruption placentae)
A thick and large placenta is termed?
placentomegaly
Usually chorioangioma does not carry any risks to the mother/ fetus, although larger chorioangioma have been associated with:
polyhydramnios, intrauterine growth restrictions(IUGR), & fetal hydrops
Uterine synechiae have be associated with:
premature rupture of membranes, premature delivery, & placental abruption
The placenta becomes the means of ________________ for the fetus.
respiration
Partial abruption often results in only a few centimeters of ___________.
separation
What is exsanguination of the fetus?
severe blood loss
Marginal abruption is also known as?
subchorionic hemorrhage
What is another name for an accessory lobe of the placenta?
succenturiate lobe
With placenta percreta the placenta can even invade:
the UB, thus causing urinary complications
What is the Chorionic plate of the placenta?
the element of the placenta closest to the fetus
The Placental substance contains?
the functional parts of the placenta
Placenta previa is evident when the placenta covers:
the internal os of the cervix
What is prone to happen with vasa previa?
the vessels are prone to rupture as the cervix dilates
Amniotic bands are typically _______, or may not be seen & are associated with _________ ____________.
thinner fetal anomalies
What is one major function of the placenta?
to act as an excretory organ for the fetus, performing imperative changes of waste products & gases with valuable nutrients & oxygen from the mother.
The correlation with C-section is theorized to be the result of ________ ______ formation from surgery, with subsequent implantation of the next placenta in that area.
uterine scar
With Placental accreta the placenta may attach to:
uterine scar following a previous c-section and/or uterine surgery
What are linear bands of scar tissue within the uterus?
uterine synechiae
What is referred to as amniotic sheets?
uterine synechiae
A circumvallate placenta may lead to:
vaginal bleeding & placental abruption
The complication of fetal vessels resting over the internal os of the cervix is referred to as?
vasa previa
Vasa previa is often associated with:
velamentous cord insertion & possibly a succenturiate lobe
How many vessels are in the umbilical cord?
(3) 2 arteries and 1 vein
Functions of the placenta:
*Gas transfer *Excretory function *Water balance *pH maintenance *Hormone production *Defensive barrier