The document describes the anatomy and development of the placenta and discusses some common abnormalities. It notes that the placenta establishes a connection between the mother and fetus to allow for nutrient/waste exchange. During development, trophoblast cells form villi that invade the uterine wall. The three layers of the placenta each have specific functions in nutrient exchange and hormone production. Some abnormalities can cause issues like abnormal bleeding, fetal growth restriction, or stillbirth if not properly managed. Ultrasound is used to diagnose many placental abnormalities prenatally.

1. Development Of Placenta And
Abnormalities
Dr. Bhoomika

2. Objectives
• To describe the anatomy of placenta
• To discuss the development of placenta
• To enumerate the functions of placenta
• To describe abnormalities of placenta and
their clinical significance

3. The Placenta
• Discoid
• Hemochorial
• Deciduate
• Establishes connection between the mother
and fetus through the umbilical cord

4. Types of Placenta
• Epithelio-chorial
placenta (swine,
horse)
• Endothelio-chorial
placenta (dog, cat)
• Hemo-chorial
placenta (human,
rodents, primates)

5. Normal Placenta
 Shape- Round to oval
 Weight- 470g
 Diameter- 22 cm
 Central thickness- 2.5 cm

6.  Maternal surface
• Develop from decidua basalis
• rough, shaggy, fleshy
• 15-30 cotyledons.
 Fetal surface
• Develops from chorion frondosum
• Smooth and shiny
 Umbilical cord
• Length is 30-70 cm
• Consists 2 umbilical arteries and 1 umbilical vein
• Single umbilical artery associated with congenital
anomalies.

7. Development Of Placenta

8. Outer cell mass
Cytotrophoblast
• Well demarcated cell
border
• Single nucleus
• Undergo DNA
synthesis and mitosis
Syncytiotrophoblast
• No cell boundaries
• Amorphous cytoplasm
• Multiple nuclei varying in
size and shape
• Interconnected cavities
developed within this
syncytium called as lacunae.

12.  Beginning Of Utero-placental circulation:
• Syncytiotrophoblast produce destructive enzymes
Destroy
Arteriole Venule
High pressure system Low pressure system
Blood will fill lacunar system Receives lacunar blood back
into maternal circulation

13. Formation of chorionic villi
Three stages:
1. Primary villus:
• Cytotrophoblast core covered
by syncytiotrophoblast.
• Formed on 12th -13th day
2. Secondary villus:
• Extraembryonic mesoderm
invades the centre of each
primary villus.
• Formed by 16th day.
3. Tertiary villus:
• Fetal blood vessels grow in the
mesoderm forming the core of
each villus.
• Formed by 21st day.

14. Decidua
• Specialised highly modified
endometrium of pregnancy.
• Three parts:
1. Decidua basalis- Directly
beneath blastocyst implantation
- Chorionic villi in contact with
Decidua basalis proliferate
Chorion frondosum
2. Decidua capsularis- Overlies
enlarging blastocyst
- Villi in contact with Decidua
capsularis degenerate Chorion
laeve.
3. Decidua parietalis- Lines
remainder of uterus

15. Functions Of Placenta
1. Exchange of substances:
a. Simple diffusion- across semipermeable
membrane, e.g. O2 and CO2.
b. Facilitated diffusion- Involvement of active
carrier systems, e.g. glucose and vitamins
c. Active transfer- across the concentration
gradient, e.g. amino acids
d. Pinocytosis- Immunoglobulin G molecules.

16. 2. Endocrine Function: secretes hormones
-hCG
-estrogen
-progesterone
-hPL
3. Barrier Function:
Usually substances of high molecular weight (> 500
daltons) do not cross the placenta.

17. Only IgG can cross the placental barrier
Viruses - rubella, CMV, HIV, Hepatitis B, Varicella zoster
Bacteria- treponema pallidum
Protozoa- toxoplasma gondii , malarial parasite
Drugs
4.Metabolic functions :
glycogen
lipids

18. Abnormalities Of Placenta
Shape and Size Variants:
• Bilobed Placenta: Cord
inserts between the two
placental lobes- either
into a connecting
chorionic bridge or into
intervening membranes.
• Multilobed Placenta:
contain three or more
equivalently sized lobes.

19. Succenturiate lobes:
- Small accessory lobes ≥1,
develop in the membranes at a
distant from the main placenta.
- These lobes have vessels that
course through membranes.
Clinical significance:
Retained in the uterus after delivery and may cause
PPH.

20. • Placenta membranacea:
- Villi cover nearly all of
the uterine cavity.
• Ring Shaped Placenta:
- Partial or complete ring
of placental tissues
present.
Clinical significance:
-APH
-PPH
-Fetal growth restriction

21. Extrachorial Placentation
Basal plate< chorionic plate
• Circummarginate
placenta:
-Fibrin and old hemorrhage
lie between the placenta
and the overlying sheer
amniochorion.

22. Circumvallate
placenta:
-Amnion and
chorion are folded
and rolled back to
form a ring leaving
a rim of uncovered
placental tissue.

23. Clinical Significance:
Increased risk for - Antepartum bleeding
- Abruption
- Fetal demise
- Preterm birth

24. • Placenta Fenestrata:
- Central portion of placental
disc is missing.

25. Chorioangioma
• Most common benign tumors of placenta
• Incidence is approximately 1 %
• Components- Blood vessels and stroma of chorionic villus
• Clinical significance:
 Small tumors-
Asymptomatic
 Large tumors (> 4cm)-
can create arteriovenus shunting within placenta to cause high
output failure, hydrops and fetal death.

26. Diagnosis:
• Ultrasonography
- well- circumscribed
- Rounded
- Hypoechoic lesion
• Colour doppler
- Increased blood flow

27. Cord Abnormalities
Based on length
Long cord
- More than 70 cm
Clinical significance:
• Cord prolapse
• Cord entanglement
• Fetal anomalies
Short cord
Less than 30 cm
Clinical significance:
• Congenital malformations
• Intrapartum distress

28. Based on insertion
Marginal
-Cord anchors at the
placental margin
-May be seen in up to 6%
cases
-Rarely causes problems
- Also called as Battledore
placenta
Velamentous
-Umbilical cord is inserted into
chorioamniotic membranes
-Incidence is 1%
-More common with twins
-Clinical significance:
• Vessels are vulnerable to
compression and may lead to
fetal hypoperfusion
• Still birth
• Preterm labour
• IUGR

29. Velamentous InsertionMarginal Insertion

30. Vasa Previa
• Umbilical vessels travel within the membrane and
overlie the cervical loss
• They can be torn with cervical dilatation or
membrane rupture and can lead to rapid fetal
blood loss
• Incidence- 2 to 6 per 10,000 pregnancies
• Antepartum diagnosis greatly improves the
perinatal survival rate
• Management- Early scheduled cesarean
delivery

32. Single Umbilical Artery
• When only one umbilical artery in an umbilical cord.
• Two types:
1. Isolated SUA- isolated ultrasound finding without
any other anomaly.
- Increased incidence of fetal growth restriction
2. Non-isolated SUA- Associated with structural or
chromosomal abnormalities.
-Most frequent anomalies are cardiovascular and
genitourinary.
-Karyotype abnormalities have been reported in 45 %
fetuses.

33. • Management: Thorough prenatal ultrasound
examination to look for all anomalies specially of
heart and kidneys.
- Fetal ECHO should be done.
- In non- isolated SUA, amniocentesis is indicated
as aneuploidies are common in them.
- Four weekly USG for fetal growth parameters .
- Weekly non- stress test and biophysical scoring
after 32 weeks till delivery.

34. THANK YOU