PLACENTA

CLINICAL ASSESSMENT.
By : Sir, Mkangi Sospeter.
University of Dodoma-Tanzania
College of health sciencies-CoHS
School of Nursing and public health
 Introduction
• Placenta is derived from the Greek word,
plakuos, meaning flat cake and this reflects its
typical appearance.
• Placenta is a foetal organ of pregnancy, which
is responsible for providing nutrition and
oxygen to the foetus as well as excretory
functions.
 Embryology
• Placenta is formed by foetal and maternal
components
• Maternal component - decidua placentalis is the
inner portion of the placenta, which is formed by
trophoblastic invasion of endometrium
• Fetal component - chorion frondosum is formed
by an arterial plexus (branches of umbilical
artery), protruding into intervillous spaces as
chorionic villi
 Gross anatomy
• The placenta normally lies along the anterior or
posterior wall of uterus and may extend to lateral
wall with increasing gestational age .
• The term placenta weighs ~470g to 500g and
measures ~22cm in diameter with a thickness of
2.0-2.5cm 3.
• Placental thickness is usually directly proportional
to gestation age, to the extent that it can often
predict the gestation weeks (e.g. 21 mm
thickness at 21 weeks gestation).
 Examination of the Placenta
• A one-minute examination of the placenta
performed in the delivery room provides
information that may be important to the care of
both mother and infant.
• The findings of this assessment should be
documented in the delivery records.
• During the examination, the size, shape,
consistency and completeness of the placenta
should be determined, and the presence of
accessory lobes, hemorrhage, tumors and
nodules should be noted
• The umbilical cord should be assessed for
length, insertion, number of vessels,
thromboses, knots and the presence of
Wharton's jelly.
• The color, luster and odor of the fetal
membranes should be evaluated, and the
membranes should be examined for the
presence of large (velamentous) vessels
• Tissue may be retained because of abnormal
lobation of the placenta or because of placenta
accreta.
• Numerous common and uncommon findings of
the placenta, umbilical cord and membranes are
associated with abnormal fetal development and
perinatal morbidity.
• The placenta should be submitted for pathologic
evaluation if an abnormality is detected or certain
indications are present.
 Clinical Characteristics of the Normal
Placenta
• A fresh, term, healthy placenta is approximately 15 –
20 cm in diameter, 2.0 to 2.5 cm thick and height
ranges between 40 -60cm. It generally weighs
approximately 5-600gms (1/6 of the baby’s birth
weight)
• The maternal surface of the placenta should be dark
maroon in colour and should consist of around 20
cotyledons. The structure should appear complete,
with no missing cotyledons.
• The fetal surface of the placenta should be shiny, gray
and translucent enough that the color of the
underlying maroon villous tissue may be seen.
• The normal cord contains two arteries and one
vein. During the placental examination, the
delivering physician 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.
• Fetal membranes are usually gray, wrinkled, shiny
and translucent. It consist of two layers; the
amnion and the chorion
 Procedure: examination of the
placenta
• Explain the procedure to the parents and ask if they wish to
observe.
• Ensure that there is adequate lighting to check the
placenta. If the lighting in the delivery room is dim, it is
advised that the placenta is examined in an alternative
location where there is adequate lighting
• Prepare a flat surface with protection to avoid blood
spillage.
• Prepare syringe and needle if cord samples are required
• Wearing an apron and gloves lay the placenta fetal side
uppermost, noting the size, shape, smell and colour.
• Examine the cord, noting the length, insertion point and
presence of true knots orthrombi.
• Inspect the umbilical cord vessels at the cut end at the
furthest point from the placenta as the arteries can be fused
around the insertion site making it difficult to differentiate
them.
• Observe the fetal side for irregularities such as succenturate
lobes, missing cotyledons, fatty deposits or infarctions
• Lift the placenta up by the cord, by doing this the membranes
can be observed for completeness. There is usually a single
hole where the baby passes through the membranes
• Return the placenta to the surface and spread out the
membranes to look for extra vessels, lobes or holes in the
surface. Separate the amnion from the chorion by pulling the
amnion back over the base of the umbilical cord to ensure
both are present.
• Turn the placenta over to inspect the maternal surface.
• Examine the cotyledons, ensuring all are present,
noting the size and any areas of infarction, blood clots
or calcification. Retain the clots to make an accurate
assessment of blood loss.
• The lobes of a complete placenta fit neatly together
without any gaps with the edges forming a uniform
circle. Broken fragments of cotyledon should be
carefully replaced before making an accurate
assessment. e.g. succenturate lobes, missing
cotyledons, fatty deposits or infarctions.
• Where there is suspicion that the placenta
and/or membranes are incomplete, they
should be kept for further inspection and
referred to the duty obstetrician.
• Inform the mother of your findings
• Complete documentation in the woman’s
health care record.
 Interpretations
Placental Size:
• Placentas less than 2.5 cm thick are associated
with intrauterine growth retardation of the
fetus.
• Placentas more than 4 cm thick have an
association with maternal diabetes mellitus,
fetal hydrops and intrauterine fetal infections
Placental Consistency and Surfaces
A: Maternal Surface. In a term infant without anemia, the
maternal surface of the placenta should be dark maroon. In
a premature infant, the placenta is lighter in color.
• Pallor of the maternal surface indicates the presence of
fetal anemia, which may be a sign of hemorrhage. With
prompt recognition of fetal hemorrhage (such as occurs in
vasa previa), lifesaving transfusion can be performed.
• Clots on the maternal surface, particularly adherent
centrally located clots, may represent placental abruption.
B: Fetal Surface. A thick ring of membranes on the fetal
surface of the placenta may represent a circumvallate
placenta which is associated with prematurity, prenatal
bleeding, abruption, multiparity and early fluid loss. A
similar but thinner ring of membrane tissue represents a
circummarginate placenta
Umbilical Cord
• While opinions of authorities differ with regard to the
limits of normal for cord length, 40 to 70 cm would appear
to be a reasonable range. A short cord is associated with a
less active fetus, fetal malformations, myopathic and
neuropathic diseases, Down syndrome and
oligohydramnios.
• Short cords may result in cord rupture, hemorrhage and
stricture. Cords of insufficient length may also result in
breech and other fetal malpresentations, a prolonged
second stage of labor, abruption and uterine inversion.
• The umbilical cord may become excessively long because of
fetal hyperkinesis. Long cords are associated with
entanglements, torsion, knots and thromboses.
Cord Vessels
• The umbilical cord typically contains two arteries and a
single vein. If only one artery and one vein are grossly
visible, the fetal anomaly rate is nearly 50 percent. These
anomalies may affect the cardiovascular, genitourinary or
gastrointestinal system, and other systems as well.
Free Fetal Membranes
• Fetal membranes should be thin, gray and glistening. Thick,
dull, discolored or foul-smelling membranes indicate the
possibility of infection.
• The nature of the odor may provide a clue to the infecting
organism: a fecal odor may indicate Fusobacterium or
Bacteroides, while a sweet odor may indicate Clostridium
or Listeria
Refferences
• JOSEPH F. YETTER et al, Examination of the
Placenta.
• Maternity Guidelines – Checking the placenta
after delivery .