Placental Pathology
AnS 536
Spring 2016
The Placenta
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The placenta is an endocrine organ, a site of
synthesis, and selective transport of
hormones and neurotransmitters.
In addition, the placenta forms a barrier to
toxins and infective organisms.
Most of the known cause cases of stillbirths
are caused by placental lesions/
abnormalities, then infections, and then
umbilical cord abnormalities.
Placental Pathology
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There are some situations when pathologists are more inclined to interpret
placental messages
 Abortion
 Fetal malformation
 Intrapartum hypoxia
 Placental Lesions
 Complicated twin pregnancy
 Prematurity
 Intrauterine growth restrictions
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Pre-eclampsia
 Intrauterine death
 Infection
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Chorionic villous inflammation
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Chorioamnionitis
Abortion
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Estimated 50% of all conceptions are thought
to end in abortion
This is the body’s corrective response to an
embryonic defect
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Defect in chorionic villi
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Due to a genetic abnormality
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Tetraploidy, triploidy, or trisomy
Chorionic Villi
Placental Lesions
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Placental lesions are suggested to be associated
with illness severity shortly after birth, and with a
wide range of neonatal problems
Maternal vascular underperfusion
 Inadequate spiral artery muscling
Fetal thrombotic vasculopathy
 Thrombosis, recent or remote, in the umbilical
cord, chorionic plate or stem villus vessels
Maternal Vascular
Underperfusion
Fetal Thrombotic
Vasculopathy
Twin Pregnancy
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Very rarely a twin pregnancy identifies the newborns as
“identical”
Chorionic tissue in the membrane means that the twins
live in separate cavities.
 Rate of complications is low
Lack of chorionic tissue in the dividing membrane
signifies a monochorionic cavity which means fetal-fetal
vascular connections are present.
 Arteriovenous fistulas
 Arterio-arterial anastomoses within the chorionic plate
Arterial-arterial anastomoses
Legend:
Arteries- blue and green
Veins-red and yellow
White star- large arterioarterial anastomosis
Blue stars-several arteriovenous anastomoses
Green stars- veno-arterial
anastomoses
Infection
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Ascending amniotic infection
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Bacteria ascending from the vagina and infecting
the fetal membranes specifically the amnion and
chorion
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Neutrophilic infiltrates in the membranes, chorionic
plate, and umbilical cord
Increased hepatic granulopoiesis
Ingested and aspirated granulocytes
Formation of bronchus-associated lymphatic tissue in
the lungs
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Segmented neutrophilic granulocytes within the fetal alveoli
Prematurity
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Pre-eclampsia
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Begins after 20 weeks of normal pregnancy
Terminated on the mother’s side
Can lead to HELLP Syndrome
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Placentae are below 5th percentile for weight, size,
and display circulatory abnormalities
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Destruction of red blood cells, elevated liver enzymes,
and low platelet count
Reduces blood flow to the placenta
Amniotic infection
Intrauterine Growth Restriction
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Live-born severely growth-restricted children are
occasionally observed with placentae containing barely
30% functional tissue
Causes
 Malfunction in the nutritional supply line
 A genetic condition
 Toxins
 Impaired maternal blood flow through the intervillous
space
 Impaired fetal blood flow through the cord and
allantoic vessels or chorionic villi
Intrauterine Death
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3-4 of 1000 pregnancies that have progressed to fetal
viability will result in sudden infant death syndrome.
Fetus has died from hypoxia, as either a single or
repeated event
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Premature abruptio
At autopsy, hypoxic hemorrhages are seen in the pleura,
pericardium, and meninges
Placental dysmaturity or placental maturation defect
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Placentae are of normal size with a pale cut surface
This is due to defective formation of both the sinusoidal vessels
in the terminal villi and the syncytiocapillary membranes
Real Life Example
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Pine Needle Abortion
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Ponderosa pine needles
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Diterpene abietane acids
Symptoms
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Severe Illness after abortion
Weak calves and prone to respiratory problems
Retained placentae
Endometritis
Renal and neurological lesions
Decline in Perinatal Postmortem
Examinations
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Examination of the placenta should be done in every
pregnancy failure, in children who survive birth but have an
unexplained low Apgar score, infection, or growth
retardation.
When babies enrolled in a trial do go on to die, parents are
not always asked about doing a postmortem examination.
Reasons as to why a PM does not occur.
 Prematurity
 Lower birth weight
 Specific diagnosis
 ie. Birth asphyxia
Professional Views on PM
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In general, the sample saw the importance of the PM as
being strongly related to the cause of death; whereas
only 31% felt that they were very important when the
cause of death was extreme prematurity, when the
cause of death was congenital anomaly, 94%, or an
indeterminate cause only 91% felt they were very
important.
17% of the sample indicated that they do not approach
families that are upset.
Parental Views on PM
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45% of parents who did not permit a PM
stated that they had not been approached.
81% of the responding parents had taken up
the offer of a PM.
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24% of these did so to contribute to research