1. IN THE NAME OF GOD

2. PLACENTA
DR.E. ZAREAN

4. Zygote

5. Pregnancy: Level 1
Fertilisation
Cell division
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6. First week

7. Fertilisation
Cell division
Wafted along Fallopean tube into uterus
(or Oviduct)

8. Cleavage and blastocyst formation:
This cleavage starts within 24 hours of fertilization and occurs nearly every 12 hours repeatedly
The resultant 16 cells mass is called morula which reaches the uterine cavity after about 4 days from fertilization.

11. Cleavage and blastocyst formation:
A cavity appears within the morula converting it into a cystic structure called blastocyst.
The cells become arranged into an :
Inner mass (embryoblast) which will form all the tissues of the embryo, and an
Outer layer called trophoblast which invade the uterine wall.

12. Cleavage and blastocyst formation:
The blastocyst remains free in the uterine cavity for 3-4 days, during which it is nourished by the secretion of the endometrium (uterine milk).

16. blastocyst
Endometrium
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17. Wafted along Fallopean tube Implantation in uterine wall
Fertilisation
Cell division
Wafted along Fallopean tube
Implantation in uterine wall
Secretory duct
Capillary
Endometrium
Trophoblast
Uterine epithelium
Embryo
Yolk sack
Blastocoel
Blastocyst
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18. Placenta formation
Lacunae form within synctiotrophoblast--maternal blood fills these spaces
Vili form with embryonic capillaries down middle

19. The decidua:
It is the thickened vascular endometrium of the pregnant uterus.
The glands become enlarged, tortuous and filled with secretion.
The stromal cells become large with small nuclei and clear cytoplasm, these are called decidual cells.

20. After implantation, the trophoblast differentiates into 2 layers:
Chorion:
After implantation, the trophoblast differentiates into 2 layers:
a. An outer one called syncytium (syncytiotrophoblast) which is multinucleated cells without cell boundaries,
b. An inner one called Langhan’s layer (Cytotrophoblast) which is cuboidal cells with simple cytoplasm.
A third layer of mesoderm appears inner to the cytotrophoblast.

21. Chorion:
The trophoblast and the lining mesoderm together form the chorion.
Mesodermal tissue ( connecting stalk) connects the inner cell mass to the chorion and will form the umbilical cord later on.

23. Chorion:
The outer syncytium and inner Langhan’s cells form buds surrounding the developing ovum called primary villi.
When the mesoderm invades the center of the primary villi they are called secondary villi.
When blood vessels (branches from the umbilical vessels) develop inside the mesodermal core, they are called tertiary villi.

24. Primary villous
Secondary villous

25. Transverse section of tertiary villous

26. Amnion:
After implantation, cavities appear in the inner cell mass; the amniotic cavity and yolk sac and in between these 2 cavities the mesoderm develops.

28. Functions of the placenta
Fertilisation
Cell division
Wafted along Fallopean tube
Implantation in uterine wall
Formation of placenta
Functions of the placenta
Supply oxygen and nutrients
Remove waste products and CO2
Provide a barrier between mother and fetus who are
genetically and immunologically different
Endocrine organ (human chorionic gonadotrophin,
oestrogen and progesterone
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29. Hormonal control of pregnancy Phase 1
Corpus luteum
Oestrogen and progesterone
Stimulated by luteinising hormone (LH) from pituitary
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30. Hormonal control of pregnancy
Phase 2
Trophoblast and early placenta
Produces human chorionic gonadotrophin (hCG)
This has LH like effects on corpus luteum
hCG is a peptide hormone
Basis of most pregnancy tests (antibody)
(appears in urine)
Responsible for “morning sickness”
Also a growth hormone/prolactin analogue from trophoblast (human placental lactogen, hPL)
Increases growth of many tissues and mammary glands
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31. Hormonal control of pregnancy
Phase 3
The placenta becomes the dominant source of oestrogen and progesterone
Also secretes
human chorionic gonadotrophin
human placental lactogen
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32. Blood levels of hormones during gestation, 40 weeks
Progesterone
hCG
Oestrogen
hPL
Blood concentration
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End lastperiod
Parturition

33. Progesterone
hCG
Oestrogen
hPL
Blood concentration
weeks

34. Next slide

36. Placenta formation
Villi bathed in maternal blood in lacunae--exchange of nutrients, O2, CO2
After 13 weeks, full placenta--pancake-shaped organ.

40. Placental Abnormalities
Abnormalities of the Membranes
Umbilical cord Abnormalities

41. Normal placenta (term placenta )
diameter : cm
thickness : 2.0 ~ 2.5 cm
weights : approximately 470 g (about 1 lb).
Placental and fetal size and weight roughly correlate in a linear fashion
Fetal growth depends on placental weight which is less with small- -for- gestational age infants

42. Clinical significance
Abnormality
Definition
Clinical significance
Multiple Placentas with a single fetus
Placenta bipartita or bilobata
- the placenta is separated into lobes
- division is incomplete and the vessels
of fetal origin extend from one lobe to
the other before uniting to form the
umbilical cord
Placenta duplex, triplex
two or three distinct lobes are separated
entirely and the vessels remain distinct.
Bilobed placenta
Succenturiate lobes
small accessory lobe ≥1, develop in
the membranes at a distant from the
periphery of the main placenta, to
which they usually have vascular
connections of fetal origin
incidence : 5%
retained in the uterus
after delivery and may
cause serious hemorrhage
accompanying vasa previa
- dangerous fetal hemorrhage at
delivery

43. Clinical significance
Abnormality
Definition
Clinical significance
Membranaceous Placenta
all of the fetal membranes are
covered by functioning villi and the
placental develops as a thin
membranous structure occupying
the entire periphery of the chorion
serious hemorrhage d/t associated placenta previa or accreta
Ring – shaped Placenta
Placenta is annular in shape and
sometimes a complete ring of placental
tissue
Variant of membraceous placenta
- tissue atrophy in a portion of the
ring a horseshoe shape in more
common
Incidence : < 1/6000 deliveries
Antepartum & postpartum bleeding and fetal growth restriction

44. Clinical significance
Diagnosis
Definition
Clinical significance
Fenestrated Placenta
Central portion of a discoidal placenta
is missing
In some instances, there is an actual
hole in the placenta but more often
the defect involves only villous tissue
with the chorionic plate
mistakenly considered to indicate that a missing portion of placenta
Placenta
Accreta
Increta
Percreta
serious variations in which
trohpoblastic tissue invade the
myometrium to varying depths
much more likely with placenta
previa or with implantation over a
prior uterine incision or perforation
Torrential hemorrhage

45. Clinical significance
Abnormality
Definition
Clinical significance
Extrachorial Placentation
Circumvallate
Placenta
Circummarginate
placenta
When the chorionic plate, which is on the
fetal side of the placenta, is smaller than
the basal plate, which is located on the
maternal side, the placental periphery is
uncovered
Fetal surface of such a placenta presents
a central depression surrounded by a
thickened, grayish-white ring.
Ring : composed of a double fold of
amnion and chorion with degenerated
decidua and fibrin in between
Within the ring, the fetal surface presents
the usual appearance, except that the
large vessels terminate abruptly at the
margin of the ring
Ring dose not have the central depression with the fold of membranes
Antepartum hemorrhage
- from placental abruption
and fetal hemorrhage
Preterm delivery
Perinatal mortaliy
Fetal malformations
less well defined

46. Placental Abnormalities
Placental calcification

47. Placental Abnormalities -Tumors of the Placenta-
Gestational Trophoblastic Disease
Chorioangioma(Hemangioma)
Tumors Metastatic to the Placenta
Embolic Fetal Brain Tissue

48. Placental Abnormalities -Tumors of the Placenta-
Chorioangioma (Hemangioma)
The resemblance components to the blood vessels and stroma of the chrionic villus
Benign tumors of placenta
Incidence : 1%
Diagnosis
: larger chorioangiomas – sonographic findings
Associated symptome
- small growths : asymptomatic
- large tumors : hydramnios or antepartum hemorrhage
Complication
: associated with low birthweight
: fetal death and malformations are uncommon

49. Chorioangioma (Hemangioma)

50. Abnormalities of the Membranes
Meconium Staining
Chorioamnionitis
Other Abnormalities

51. Abnormalities of the Membranes - Meconium Staining -
Incidence : %14-20
Preterm fetuses seldom pass meconium.
<38 wks : uncommon
>42 wks : increase to 25~30%
Staining of the amnion can be obvious within 1~3hours after meconium passage
Although more prolonged exposure results in staining of the the chorion, umbilical cord and decidua, meconium passage cannot be timed or dated accurately .

52. Abnormalities of the Membranes - Meconium Staining -
Incidence : %14-20
Preterm fetuses seldom pass meconium.
<38 wks : uncommon
>42 wks : increase to 25~30%
Staining of the amnion can be obvious within 1~3hours after meconium passage
Although more prolonged exposure results in staining of the the chorion, umbilical cord and decidua, meconium passage cannot be timed or dated accurately .

53. Abnormalities of the Membranes - Meconium Staining -
Study
Meconium Passage(%)
Eden and associates(1987)
39weeks 14
40weeks 19
42weeks 26
>42weeks 29
Usher and colleagues(1988)
39-40 weeks 15
41 weeks 27
42 weeks or greater 32
Steer and co-workers(1989)
<36 weeks 3
36-39 weeks 13
40-41 weeks 23

54. Abnormalities of the Membranes - Meconium Staining -
Clinical significance
: perinatal morbidity and mortality↑
- severe fetal acidemia (cord arterial pH < 7 )
- cesarean delivery : doubled ( 7-14%)
: neonatal morbidity and mortality ↑
- meconium aspiration syndrome (10% of exposed infants)
: serious maternal risk ↑
- associated with amnionic fluid embolism
→ increases maternal mortality from cardiorespiratory failure
and consumptive coagulopathy
- Puerperal metritis : 4 times

55. Abnormalities of the Membranes -Other Abnormalities-
Definition & causes
Clinical significance
Amnionic cyst
lined by typical amnionic epithelium
fusion of amnionic folds with
subsequent fluid retention
Amnion nodosum
tiny, light tan , creamy nodules in the
amnion made up of vernix caseosa
with hair, degenerated squames and
sebum
Oligohydramnios
Found in
fetuses with renal agenesis
prolonged preterm ruptured
membranes
the placenta of the donor
fetus with twin-to-twin
transfusion syndrome
Amnionic band
caused when disruption of the amnion
leads to formation of bands or strings
that entrap the fetus and impair growth
and development of the involve
structure
Intrauterine amputation

56. Umbilical Cord Abnormalities
Length
: appreciable variation, extremes range
- no cord(achordia) ~ lengths<300cm
- mean length : 37cm
- excessively long cords : ≥ 70cm ( ≥2 SD )

57. Umbilical Cord Abnormalities
Short umbilical cords
: associated with adverse perinatal outcomes such as fetal growth
restriction, congenital malformations, intrapartum distress and
risk of death (doubled)
Excessively long cords
: associated with
- maternal systemic disease and delivery complications such as
prolapse, cord entanglement, fetal distress, fetal anomalies and
respiratory distress

58. Umbilical Cord Abnormalities
Determinants of cord length
- concept that cord length is influenced positively by both the
volume of amnionic fluid and fetal mobility
- heredity
Miller and associates identified the cord to be shortened appreciably when there had been either chronic fetal constraint from oligohydramnios or decreased fetal movement, such as with Down syndrome or limb dysfunction
Long cord
Short cord

59. Umbilical Cord Abnormalities Cord Coiling
Umbilical vessels : in a spiraled manner
Hypocoiled cords
increase in various adverse outcomes in fetuses
meconium staining, preterm birth and fetal distress
Hypercoiled cords
higher incidence of preterm delivery and cocaine abuse

60. Umbilical Cord Abnormalities Abnormalities of Cord insertion
: usually inserted at or near the center of the fetal surface of the
placenta
Furcate insertion
Marginal insertion
Velamentous insertion
Vasa Previa

61. Umbilical Cord Abnormalities
Anomalities
Definition
incidence
Significance
Furcate insertion
Umbilical vessels separate from the cord substance before their insertion into the placenta
Rare
Margnial Inserion
Battledore placenta
: cord insertion at the placental
margin
7% at term
Cord being pulled off during delivery of the placenta
Velamentous Insertion
Umbilical vessels separate in
the membranes at a distance
from the placental margin
Reach surrounded only by a
fold of amnion
1.1%
more frequently
with twins
28% of triples

62. Umbilical Cord Abnormalities Abnormalities of Cord insertion
Vasa Previa
Associated with velamentous insertion when some of the fetal vessels in the membranes cross the region of the cervical os below the presenting fetal part
Incidence : 1/5200 pregnancies
- ½ : associated with velamentous inserion
- ½ : marginal cord insertions and bilobedor, succenturiate-lobed
placentas
Risk factors
- bilobed , succenturiate or low-lying placenta
- Multifetal pregnancy
- Pregnancy resulting from in vitro fertilization

63. Umbilical Cord Abnormalities Abnormalities of Cord insertion
Diagnosis
: color Doppler examination (low sensitivity with ultrasound)
- Perinatal diagnosis : associated with increased survival (97:44)
- Antenatal diagnosis : associated with decreased fetal mortality
compared with discovery at delivery
Hemorrhage antepartum or intrapartum
: vasa previa and a ruptured fetal vessel exists
Detecting fetal blood
- Apt test
- Wright stain : to smear the blood on glass slides stain the smears
with Wright stain and examine for nucleated RBC
- normally are present in cord blood but not maternal blood
- risk of low lying placenta : 80%

64. Umbilical Cord Abnormalities Abnormalities of Cord insertion
Diagnosis
: color Doppler examination (low sensitivity with ultrasound)
- Perinatal diagnosis : associated with increased survival (97:44)
- Antenatal diagnosis : associated with decreased fetal mortality
compared with discovery at delivery
Hemorrhage antepartum or intrapartum
: vasa previa and a ruptured fetal vessel exists
Detecting fetal blood
- Apt test
- Wright stain : to smear the blood on glass slides stain the smears
with Wright stain and examine for nucleated RBC
- normally are present in cord blood but not maternal blood
- risk of low lying placenta : 80%

65. Cord Abnormalities capable of impeding blood flow
Knots
false
Result from kinking of the vessels to accommodate to the length of the cord
True
Result from active fetal movements
Venous stasis
→ mural thrombosis and fetal hypoxia,
causing death or neurological
morbidity
Incidence : 1.1%
Stillbirth incidence : 6%
esp)
high incidence : monoamnionic twins
False knot(Lt), true knot (Rt)

66. Umbilical Cord Abnormalities Cord Abnormalities capable of impeding blood flow
Loops
: Coiled around portions of the fetus, usually the neck.
longer cords
- one loop of nuchal cord : 20~34%
- Two loops in 2.5 ~ 5%
- three loops : 0.2~0.5%

67. Umbilical Cord Abnormalities Torsion and Strictures
Incidence : rare
Result from fetal movements during which the cord normally becomes twisted
fetal circulation is compromised
Stricture
More serious
Most infants with this finding are stillborn
Associated with an extreme focal deficiency in Wharton jelly
In monoamnionic twinning, a significant fraction of the high perinatal mortality rate is attributed to entwining of the umbilical cords before labor

68. Placental Abnormalities - Abnormal Shape or Implantation-
Circumvallate(left) and cricummarginate(right) variaties of extrachorial placentas

69. Placental Abnormalities - Abnormal Shape or Implantation-
Anomaly of Placental site

70. Velamentous Insertion

71. Vasa previa
Internal cx os