4. • Definition
• placenta is a temporary organ joining
the mother and fetus for nutritional and
excretory needs in a rapidly growing
fetus, expelled during the birth process
with the fetal membranes.
5. • Function
The placenta serves as an interface between the mother and the
developing fetus and has three main jobs:
1. Attach the fetus to the uterine wall.
2. Provide nutrients to the fetus.
3. Allow the fetus to transfer waste products to the mother's blood.
7. Development
•Implantation and early placentation
•Implantation and lacunar period
•Transition from the lacunar period to the
primitive villous tree
•Development of the uteroplacental and
umbilicoplacental vascular beds
12. Abnormalities of the position
•Normally implantation and the formation
of placenta take place in the upper
posterior part of the uterus. When it is
present in the lower uterine segment the
condition is called placenta previa.
• It can lead to severe antepartum
haemorrahage and difficulty in delivery.
13. •Various types or degrees of the placenta
previa are shown in the figure :
14. Abnormalities of the shape
•Lobed placenta
(P. bipartate or
P. tripartate) :
• Placenta is divided into
2 or 3 lobes. Each lobe
has separate branch
from umbilical vessel.
17. •Marginal or battledore placenta : In this
type the umbilical cord is attached to
the margin of the placenta.
18. Abnormal placental invasion
• These clinically important placental abnormalities
develop when trophoblast invades the myometrium
to varying depths to cause abnormal adherence. They
are much more likely when there is placenta previa
or when the placenta implants over a prior uterine
incision or perforation
1. Placenta Accreta : chorionic villi attach to the
myometrium
2. Placenta Increta : chorionic villi invade into the
myometrium
3. Placenta Percreta : chorionic villi penetrate through
the myometrium to reach the uterine serosa
21. References
• Gardosi J, Kady SM, McGeown P, Francis A, Tonks A:
Classification of stillbirth by relevant condition at death (ReCoDe):
population based cohort study. British Medical Journal. 2005, 331:
1113-1117. 10.1136/bmj.38629.587639.7C.
• https://study.com/academy/lesson/the-placenta-and-the-fetus-
structure-and-function.html