very basic description for medical student esp while doing obstetrics ultrasound

1. DR REKHA KHARE
MD RADIOLOGY
The Placenta

2. Placenta
• The placenta is a temporary embryonic and
later fetal organ that begins developing from
the blastocyst shortly after implantation
• The placenta is an organ that develops in the uterus during
pregnancy.
• This structure provides oxygen and nutrients to a growing
baby. It also removes waste products from the baby's blood
• The placenta attaches to the wall of the uterus, and the
baby's umbilical cord arises from it.

3. Types of placenta
• Posterior placenta:
The placenta grows on the back
wall of uterus
• Anterior placenta:
The placenta grows on the front wall
of uterus closer to bladder
• Fundal placenta:
The placenta grows at the top of
uterus
• Lateral placenta:
The placenta grows on the right or
left wall of uterus

4. Development of placenta
• The placenta begins to develop
upon implantation of the blastocyst into
the maternal endometrium, very early on
in pregnancy at about week 4
• The outer layer of the late blastocyst, is
formed of trophoblasts, cells that form
the outer layer of the placenta.
• This outer layer is divided into two further
layers:
• the underlying cytotrophoblast layer and
the overlying syncytiotrophoblast layer.
• The syncytiotrophoblast is
a multinucleated continuous cell layer
that covers the surface of the placenta.
• The placenta grows throughout pregnancy

5. Placenta
• The placenta grows throughout pregnancy.
Development of the maternal blood supply to
the placenta is complete by the end of the
first trimester of pregnancy week 14

6. Placental circulation
• Placental circulation- maternal and
fetoplacental circulation
• maternal blood flow begins between days 5–
12, and is approximately 600–700 ml/min at
term.

7. Feto-placental circulation
• Deoxygenated fetal blood passes through umbilical arteries to the
placenta. At the junction of umbilical cord and placenta, the
umbilical arteries branch radially to form chorionic arteries.
• Chorionic arteries, in turn, branch into cotyledon arteries.
• In the villi, these vessels eventually branch to form an extensive
arterio-capillary-venous system, bringing the fetal blood extremely
close to the maternal blood; but no intermingling of fetal and
maternal blood occurs
• ("placental barrier")
• Endothelin and prostanoids cause vasoconstriction in placental
arteries, while nitric oxide causes vasodilation.
• On the other hand, there is no neural vascular regulation, and
catecholamines have only little effect.

8. Feto-placental circulation
• The fetoplacental circulation is vulnerable to
persistent hypoxia or intermittent hypoxia and
reoxygenation, which can lead to generation
of excessive free radicals. This may contribute
to pre-eclampsia and other pregnancy
complications.
• It is presumed that melatonin plays a role as
an antioxidant in the placenta.

9. Pathology of placenta
• Placenta accreta, when the placenta implants
too deeply, all the way to the actual muscle of
uterine wall (without penetrating it)
• Placenta praevia, when the placement of the
placenta is too close to or blocks the cervix
• Placental abruption, premature detachment
of the placenta
• Placentitis, inflammation of the placenta, such
as by TORCH infections

10. Placenta accreta
• Findings could be—
• focal thinning or absence of the myometrium
at the site of placental implantation
• a nodular interface between the placenta and
the uterus
• a mass effect of the placenta on the uterus
causing an outer bulge, heterogeneous signal
intensity within the placenta

11. Placenta increta and percreta
• Placenta increta is a condition where the
placenta attaches more firmly to the uterus
and becomes embedded in the organ's
muscle wall.
• Placenta percreta is a condition where
placenta attaches itself and grows through the
uterus and potentially to the nearby organs
(such as the bladder).

12. Placenta accreta

13. Placenta accreta on USG

14. Placenta accreta on USG

15. Placenta previa
• During pregnancy, the placenta provides the
growing baby with oxygen and nutrients from
the mother's bloodstream.
• Placenta previa means the placenta has
implanted at the bottom of the uterus, over
the cervix or close by, which means the baby
can't be born vaginally.

16. Placenta previa

17. Types of placenta previa

18. Placental abruption
• The placenta is an organ that develops in the
uterus during pregnancy.
• Placental abruption occurs when the placenta
separates from the inner wall of the uterus
before birth
• Placental abruption can deprive the baby of
oxygen and nutrients and cause heavy
bleeding in the mother.

19. Placental Abruption

20. Cause of placental abruption
• The cause is unknown in most cases,
• But risk factors may include maternal high
blood pressure, abdominal trauma and
substance misuse

21. Types of placental abruption
1. Subchorionic abruption - bleeding
between myometrium and placental
membranes.
2. Retroplacental abruption - bleeding
between myometrium and placenta
3. Preplacental abruption - bleeding
between placenta and amniotic fluid
4. Intraplacental abruption.

22. HAVE A NICE DAY
THANKS