placenta umbilical cord

8/14/2019 Placenta Umbilical Cord

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Dr. Firmansyah, SpOG


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The Placenta


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The placenta develops fromthe chorion frondosum

( foetal origin)

and decidua basalis( maternal origin).

Origin:


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Anatomy At Term

Shape : discoid.Diameter: 15-20 cm.

Weight: 500 gm.Thickness: 2.5 cm at its center andgradually tapers towards the periphery.

Position : in the upper uterine segment(99.5%),either in the posterior surface

(2/3)or the anterior surface (1/3).


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Surfaces

Foetal surface Maternal surface


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a. Foetal surface Smooth, glisteningand is covered

by theamnionwhich is reflected

on the cord. The umbilical cordis inserted near

or at the center of this surface andits radiating branches can be seenbeneath the amnion.


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b.Maternalsurface

Dull greyish red in colour andis divided into 15-20

cotyledons. Each cotyledon is formed of

the branches of one mainvillus stemcovered by deciduabasalis.


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(1) Respiratory function(2) Nutritive function

(3) Excretory function

(4) Production of enzymes

(5) Production of pregnancy associated plasma

proteins (PAPP)(6) Barrier function

(7) Endocrine function

Funct ions Of The Placenta


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Abnormal i t ies Of The Placen ta

(A) Abnormal Shape

(B) Abnormal Diameter(C) Abnormal Weight

(D) Abnormal Position

(E) AbnormalAdhesion


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(A) Abnormal Shape:

1. Placenta Bilobata

2. Placenta Bipartite3. PlacentaSuccenturiata

4. Placenta Circumvallata5. Placenta Fenestrata


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The placenta

consists of two

equal lobes

connected by

placentaltissue

1. Placen ta B ilobata:


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2. Placenta Bipartite:

The placenta consists of two equalparts connected by membranes.

The umbilical cord is inserted in onelobe and branches from its vesselscross the membranes to the other

lobe. Rarely, the umbilical cord divides into

two branches, each supplies a lobe.


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The placenta consists of a large lobeand a smaller one connecting together

by membranes. The umbilical cord is inserted into the

large lobeand branches of its vesselscross the membranes to the small

succenturiate (accessory) lobe.

3. Placen ta Succen tu r iata:


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3. Placen ta Succen tur iata:

The accessory lobe may be retained in

the uterus after delivery leading to

postpartum haemorrhage. This is suspected if a circular gapis

detected in the membranes from which

blood vessels pass towards the edge ofthe main placenta.


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A whitish ring composed of decidua, is seenaround the placenta from its foetal surface.

This may result when the chorion

frondosum is two smallfor the nutrition ofthe foetus, so the peripheral villi grow in

such a way splitting the decidua basalisinto a superficial layer ( the whitish ring)

and a deep layer.

4. Placen ta Circumval lata:


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It can be a cause of :

1. Abortion,

2. Ante partum haemorrhage,

3. Preterm labour and

4. Intrauterine foetal death.



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5. Placenta Fenestrata:

A gap is seen in the placenta

covered by membranes giving theappearance of a window.


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Placenta membranacea: A great part of the chorion develops

into placental tissue. The placenta is large, thinand may

measure 30-40 cmin diameter. It may encroach on the lower uterine

segment i.e. placenta praevia.

(B ) Abnormal Diameter:


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(C) Abnormal Weight:

The placentaincreases in size and weight

as in :1.Congenital syphilis,

2.Hydrops foetalis and3.Diabetes mellitus.


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Placenta Praev ia:

The placenta is partly orcompletely attached to the

lower uterine segment

(D) Abnormal Position:


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In this gravid uterus, the placenta implanted over the os.This is called placenta previa.

Implantation in this low lying position can lead to

extensive hemorrhage as the dilation of the cervix

disrupts the placenta.


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(E) Abnormal Adhesion :

Placenta Accreta: The chorionic villi penetrate deeply into the

uterine wall to reach the myometrium,due to

deficient decidua basalis. When the villi penetrate deeply into the

myometrium, it is called "placenta increta"

and When they reach the peritoneal coat it is called

"placenta percreta".


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The Umbi lical Cord

AnatomyOrigin :

It develops from the connecting stalk.Length:

At term, it measures about 50 cm.Diameter:

2 cm.


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Structure:It consists of mesodermal connective

tissue called Wharton's jelly, covered by

amnion.

It contains:1. One umbilical veincarries oxygenated blood

from the placenta to the foetus

2. Two umbilical arteriescarry deoxygenatedblood from the foetus to the placenta,

3. Remnantsof the yolk sac and allantois.

The Umbilical Cord

H i l h l bili l d


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Here is a normal three vessel umbilical cord.

Note that there are two arteriestoward the right and a

single veinat the left.

Most of the cord consists of a loose mesenchyme withintercellular ground substance (Wharton's jelly).


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Insertion:

The cord is inserted in the foetalsurface of the placenta near the

center "eccentric insertion" (70%)

Or at the center "central insertion"

(30%).

The Umbi lical Cord


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Abnormalities

Of The

Umbilical Cord


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1. Marginal insertion :in the placenta ( battledore insertion).

2. Velamentous insertion:

in the membranes and vessels connect

the cord to the edge of the placenta.

If these vessels pass at the region of theinternal os , the condition is called "

Vasa praevia".

(A ) Abnormal co rd inser t ion :


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Vasa praevia

Vasa praeviacan occur also

when the vessels connecting asuccenturiate lobe with the

main placenta pass at theregion of the internal os


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Velamentous insertion


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1. Short cord which may lead to :

i-Intrapartum haemorrhagedue to

premature separation of the placenta,ii-Delayed descentof the foetus druing

labour,iii-Inversion of the uterus.

(B ) Abno rmal cord leng th:


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2. Long cord which may lead to:

i-Cord presentationand cordprolapse,

ii-Coiling of the cordaround the neck,iii-True knotsof the cord.

(B ) Abnormal co rd length :


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(C) Kno ts o f the cord :

1. True knot: when the foetus passes through a loop of

the cord.

If pulled tight, foetal asphyxia may result.

2. False knot:

localized collection of Whartons jelly

containing a loop of umbilical vessels.


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A long umbilical cord may more easily

become twisted, or even form a knot


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(D) Tors ion o f the co rd :

may occur particularly in the portion

near the foetus where theWharton's jelly is less abundant.


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(E) Haematoma :

Due to rupture

of one of the umbilical

vessels.


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(F) Sing le umb il ical artery :

may be associated with other

foetal congenital anomalies


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Thank you

placenta umbilical cord

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