Download Placental Examination

Station 5
Dr A Cassim
At this station examine the placenta provided.
Station Learning Objectives:
1. Familiarise yourself with the examination of the placenta and be alert to
potential abnormalities.
2. Using the charts prepared revise
a. The anatomy
b. The basic physiology of placental function.
c. Histology of placenta ( note this for your interest only).Not core
Placental Examination
A one-minute examination of the placenta performed in the delivery room is
generally recommended and satisfactory for the observations you will need to make.
The findings are then usually entered into the delivery records and will serve as
the basis for the care of the mother and her infant.
A
1. Observe for:
size, shape, consistency and completeness
The presence of any accessory lobes, placental infarcts, hemorrhage and
tumors should be noted.
2. Inspect the umbilical cord for:
length, insertion, number of vessels (2 arteries and a vein) and
presence of Wharton's jelly
3. The color, luster (shine) and odour of the fetal membranes should be
evaluated
B
Note inspection and palpation should be combined.
The placental and maternal surfaces should be palpated for missing cotyledons
Missing placental tissue may indicate abnormal lobation or the type of placenta
present viz. placenta accreta, placenta increta or placenta percreta. All or part of the
placenta is retained in placenta accreta, placenta increta and placenta percreta. In
these conditions, the placental tissues grow into the myometrium to lesser or greater
depths. Manual exploration and the removal of retained placental tissue is necessary
in these cases.
The normal cord contains two arteries and one vein. During the placental
examination, you should count the vessels in either the middle third of the cord
or the fetal third of the cord, because the arteries are sometimes fused near the
placenta and are therefore difficult to differentiate.
Cross Section of Umbilical Cord
EXAMINATION OF THE PLACENTA IN THE DELIVERY ROOM
Normal
Finding
Assess
PLACENTAL
completeness
Average Placental
size
Complete
Normal
Appearance
Relevance
All cotyledons
present
Diameter: about 22
cm
Thickness: 2.0 to
2.5 cm
Weight: about 470 g
UMBILICAL CORD
Cord length
Include the fetal and maternal ends
average 40 to 70 cm.
Number of Vessels
3 (2arteries, 1 vein)
Count the number of vessels at more than 5 cm from the placental end of the cord.
Insertion
Central
MEMBRANES
Smell
Usually none
2 Fused layers
ABNORMAL
FINDINGS
PLACENTA
Placenta
Grows into
membranacea myometrium
Hemorrhage and poor fetal
outcomes
Placenta
accreta and
placenta
percreta
Probable retained placenta,
Increased incidence of
postpartum infection and
hemorrhage
Abnormalities of
SHAPE
Multiple lobes
bilobate,
bipartite,
succenturiate,
accessory.
Probable retained placental
tissue.
.
MATERNAL FETAL SURFACE
Placental
infarcts
Placental
bleeding
(e.g.,
abruption)
Firm pale or gray
areas
Old infarcts
P.I.H., S.L.E,
Advanced maternal age
Dark areas
Fresh infarcts
P.I.H., S.L.E.
Advanced maternal age
Clot, especially an
adherent clot near
placental centre,
Distortion of placental
shape
Associated with abruption
Fresh clot along the
margin. No distortion
of placental shape
Marginal hematoma: If the
clot is small, implies no
significance
PLACENTAL SIZE
Thin placenta
Less than 2
cm.
Possible placental insufficiency
with IUGR.
Thick
placenta
More than 4
cm.
Maternal diabetes
Fetal hydrops
Intrauterine fetal infection
Incomplete,
Retained
placenta
Missing bits of
Bleeding (uterus can’t
membrane/cotyledons contract).
Infection
FETAL PLACENTAL SURFACE
Fetal anemia
Pale fetal surface
Anemia in newborn
Fetal hydrops
Severe Hemorrhage.
circumvallete
placenta.
Thick ring of
membranes
Prematurity, Abruption,
Multiparity.
Early fetal loss
Circummarginate Inner membrane
placenta.
ring thinner than
outer.
May be associated with an
increase in fetal
malformations.
Fetus
papyraceus and
fetus
compressus
One or several
nodules or
thickenings
Deceased twin
May be associated with
otherwise unexplained fetal
demise
Amnionic bands
Delicate or robust
bands of amnion
Amputation of fetal parts
Fetal death
Short cord
Less than 40 cm
Poorly active fetus
Down syndrome
Decreased intelligence
quotient
Fetal malformations
Myopathic and neuropathic
disease
Cord rupture, hemorrhage or
stricture
Breech or other fetal
malpresentation
Prolonged second stage of
labor
Abruption
Uterine inversion
Long cord
More than 100 cm Fetal hyperkinesis
Thromboses
UMBILICAL CORD
Thin cord and
decreased
amount of
Wharton's jelly
Narrow areas in
the cord (normal
cord diameter is
2.0 to 2.5 cm)
Postmaturity and
oligohydramnios
Torsion and fetal death
Edema
Diffuse
Hemolytic disease
Prematurity
Cesarean section
Maternal preeclampsia
Eclampsia
Maternal diabetes mellitus
Transient tachypnea of the
newborn
Idiopathic respiratory distress
Focal
Trisomy 18 syndrome
Patent urachus
Omphalocele
Velamentous
cord insertion
Increased risk of fetal
hemorrhage from the
unprotected vessels, as well as
vascular compression and
thrombosis
Advanced maternal age
Diabetes mellitus
Smoking
Single umbilical artery
Fetal malformations
Cord knot
Fetal compromise if the knot is
tight
Entanglement
Fetal compromise, especially
at delivery
Abnormal
number of
vessels
Expect two
arteries, one vein
If only one artery is present,
up to nearly a 50 percent
incidence of fetal anomalies
Cord more prone to
compression
Other
thromboses
Clot in vessel(s) on
cut section
Fetal compromise
Color
Green
Meconium staining
Old blood from an earlier
bleeding event
Infection.
MEMBRANES
Smell
Malodorous
Possible infection
Fecal odor: possibly
Fusobacterium or Bacteroides
infection
Sweet odor: possibly Clostridium
or Listeria infection
Permission: American Academy of Family Physicians
ANATOMY OF THE PLACENTA
The amnion is a membranous sac which surrounds and protects the embryo.
The amniotic cavity is roofed in by a single stratum of flattened, ectodermal cells, the
amniotic ectoderm, and its floor consists of the prismatic ectoderm of the embryonic
disk
The Chorion is the outer lining which consists of two layers: an outer formed by the
primitive ectoderm or trophoblast, and an inner by the somatic mesoderm; with this
latter the amnion is in contact.
The trophoblast is made up of an internal layer of cubical or prismatic cells, the
cytotrophoblast or layer of Langhans, and an external layer of richly nucleated
protoplasm devoid of cell boundaries, the syncytiotrophoblast. It undergoes rapid
proliferation and forms numerous processes, the chorionic villi, which invade and
destroy the uterine decidua and at the same time absorb from it nutritive materials
for the growth of the embryo.
The umbilical cord attaches the fetus to the placenta; its length at full time, as a
rule, is about equal to the length of the fetus, i.e., about 50 cm., but it may be
greatly diminished or increased.
The normal cord contains two arteries and one vein.
On section, the placenta presents a soft, spongy appearance, caused by the greatly
branched villi; surrounding them is a varying amount of maternal blood giving the
dark red color to the placenta. Many of the larger villi extend from the chorionic to
the decidual surface, while others are attached to the septa which separate the
cotyledons; but the great majority of the villi hang free in the intervillous space.
Development of Placenta and membranes
i Early formation of Allantois and differentiation of yolk stalk
ii Later stage of development with constriction of yolk sac
iii Expansion of amnion
iv Development of umbilical cord
Placental Function
The placenta is a multifaceted organ that plays critical roles in maintaining and
protecting the developing fetus.
It serves three important functions:
1. Nutrient transfer from the mother to the fetus and waste secretion from the
fetus to the mother.
2. Acts as a barrier for the fetus against pathogens and the maternal immune
system.
3. An active endocrine organ.
Placental insufficiency / intrauterine growth restriction (IUGR) is a major cause of
increased perinatal morbidity and mortality in humans, and has recently been tied to
the predisposition of adult onset of diabetes, hypertension, stroke and coronary
heart disease