Maternal Vascular Malperfusion

Slide 1 · Maternal Vascular Malperfusion

Placental circulation, mechanisms, morphology and clinical correlation

Dr Abu Suraih Sakhri

MBBS, MD (Pathology)

www.abusuraihsakhri.com

Slide 2 · Learning objectives

By the end of the lecture, you should be able to:

Distinguish maternal intervillous perfusion from fetal villous circulation.

Explain how abnormal spiral-artery remodeling can compromise placental perfusion.

Recognize the defining constellation of MVM-associated placental lesions.

Relate placental findings to fetal growth restriction and preeclampsia.

Differentiate MVM from fetal vascular malperfusion and selected mimics.

Slide 3 · Maternal vascular malperfusion: Definition

MVM is a disorder of maternal blood delivery to the placenta.

Abnormal maternal placental circulation reduces supply to intervillous spaces.

The precipitating problem may be abnormal implantation, development, or maternal vascular disease.

MVM is identified by a constellation of placental findings—not a single obligatory lesion.

The anatomic compartment affected is the maternal side of exchange.

Slide 4 · The maternal circulation supplies intervillous blood

Chorionic plate

Decidua basalis

Myometrium

Intervillous

Maternal

Blood

Villous

Fetal

Vessels

Red arrows: Maternal inflow from spiral arteries

Schematic—not a specimen

Slide 5 · Two placental circulations must be distinguished

Maternal compartment

Fetal compartment

Blood reaches intervillous space from maternal spiral arteries.

Maternal perfusion supports transfer across villous trophoblast.

MVM concerns this incoming maternal blood supply.

Fetal vessels travel via umbilical vessels and villous capillaries.

Fetal-side obstruction may cause vascular thrombi or avascular villi.

Fetal vascular malperfusion is a different morphologic process.

Slide 6 · The chorionic villus is the exchange structure

Ordinary terminal villus

Ischemic distal villus

Fetal capillaries

Smaller villus + syncytial knots

The drawing explains features—not diagnostic thresholds or specimen appearance.

Original schematic — not a histologic specimen

Slide 7 · Why adequate maternal inflow matters

Maternal blood delivery

Intervillous perfusion

Villous exchange surface

Fetal growth support

Reduced inflow can compromise the placenta’s capacity to sustain fetal growth.

Slide 8 · Placental demand increases with gestation

The context for uteroplacental underperfusion:

Fetal nutritional demand increases rapidly in the second trimester.

A developmentally immature placenta has less reserve for exchange.

Severe perfusion abnormalities may therefore manifest before the third trimester.

Slide 9 · Causes converge on inadequate intervillous supply

Abnormal implantation

Abnormal placental development

Maternal vascular disease

Intervillous underperfusion

Each category can precipitate MVM; They are not necessarily successive steps.

Slide 10 · Maternal vascular disease as a precipitant

Maternal conditions can compromise uteroplacental blood delivery.

Maternal vascular disease can precipitate reduced placental blood supply.

Hypertension and coagulopathies appear in related discussions of pregnancy complications.

The placenta’s morphology records effects of impaired supply; It does not by itself identify a unique maternal cause.

Slide 11 · Physiologic spiral-artery remodeling changes resistance

Narrow lumen

Unremodeled artery

Wide lumen

Remodeled artery

Retained muscular wall and higher resistance

Trophoblast-mediated smooth-muscle loss

Cross-sectional schematic — not histology

Slide 12 · Normal remodeling is trophoblast mediated

Placental-bed vascular transformation is active, not passive.

Extravillous trophoblast invades maternal decidua and decidual vessels.

Vascular smooth muscle is destroyed and maternal endothelial lining is partly replaced.

The result is a large-capacity, low-resistance uteroplacental vascular bed.

Slide 13 · Failed remodeling leaves high-resistance supply

Shallow trophoblastic invasion

Persistence of muscular spiral arteries

Inadequate flow adaptation

Placental ischemia risk

Failed remodeling is a central placental abnormality in preeclampsia.

Slide 14 · Remodeled and unremodeled placental-bed arteries

Physiologic remodeling

Failure of remodeling

Large-capacity arterial channels

Smooth-muscle coat largely lost

Low-resistance uteroplacental pathway

Adapts to later gestational demand

Smaller, muscular resistance vessels persist

Reduced perfusion adaptation

Greater susceptibility to placental ischemia

Can accompany preeclampsia-associated MVM

Slide 15 · Pathogenesis connects maternal vessels to villi

Maternal vascular abnormality

Reduced intervillous inflow

Placental ischemic stress

MVM tissue lesions

The morphologic pattern follows impaired supply to the exchange compartment.

Slide 16 · Severity is a spectrum

Reduced perfusion has variable clinicopathologic expression.

At the milder end: Restricted fetal growth.

At the severe end: Uteroplacental ischemia and association with maternal preeclampsia.

Severity cannot be inferred from one lesion without considering the complete placenta and clinical context.

Slide 17 · A five-part morphologic constellation

Placental hypoplasia

Placental infarcts

Decidual arterial lesions

Ischemic villous changes

Abruption / retroplacental bleed

These findings can coexist in different combinations; None is required in every specimen.

Slide 18 · Placental hypoplasia has a size definition

Hypoplasia against gestational age.

Placental weight is below the 10th percentile for gestational age.

Interpret weight relative to age, not as an isolated absolute number.

Reduced placental mass is one component of the MVM pattern.

The book provides the percentile; This deck does not invent a gram cutoff.

Slide 19 · Placental hypoplasia changes the whole-organ assessment

Gestational-age comparison—not an absolute gram cutoff

Reference placenta

Placental hypoplasia

Weight below 10th percentile for gestational age

Slide 20 · A small placenta is not a cause-specific diagnosis

The weight criterion must be interpreted in context.

Weight alone is not sufficient to specify abnormal spiral-artery remodeling.

Examine infarcts, villous ischemia, decidual vessels, and retroplacental lesions together.

Correlate with fetal growth and maternal obstetric findings.

Slide 21 · Placental infarction localizes ischemic injury

Fetal surface / chorionic plate

Maternal surface / decidua

Infarct

Compartment schematic — not gross pathology

Slide 22 · Placental infarcts are an MVM-associated lesion

Infarction reflects tissue injury in the setting of impaired perfusion.

Placental infarction is a principal component of the MVM pattern.

In preeclampsia-associated MVM, infarcts may be large and numerous.

Interpret extent alongside the other placental lesions and pregnancy history.

Slide 23 · Why infarction follows maternal underperfusion

Restricted placental arterial supply

Insufficient regional oxygen delivery

Localized placental ischemia

Infarction of affected tissue

A causal schema derived’ placement of infarcts among ischemic MVM lesions; The diagram is conceptual.

Slide 24 · Decidual vessels provide mechanistic evidence

Placental-bed vessel pathology complements villous findings.

Failure of normal spiral-artery remodeling can be visible in decidual vasculature.

Decidual arterial thrombi may accompany MVM.

Fibrinoid necrosis and intimal lipid deposition are additional described changes.

Slide 25 · Decidual arterial lesions must be separated from villous changes

Narrow lumen

Unremodeled artery

Wide lumen

Remodeled artery

Retained muscular wall and higher resistance

Trophoblast-mediated smooth-muscle loss

Cross-sectional schematic — not histology

Slide 26 · Unremodeled spiral arteries retain a muscular phenotype

Mechanism and morphology are linked.

Normal adaptation removes smooth muscle and lowers resistance.

Failed remodeling leaves vessels less suited to high gestational perfusion demands.

An abnormal decidual vessel is not itself the same thing as a villous infarct.

Slide 27 · Decidual thrombi: Obstruction of a maternal pathway

Decidual vessel lesion

Formation of an arterial thrombus

Restriction of maternal flow

Downstream ischemic stress

Decidual-vessel thrombi may occur within the MVM morphologic pattern.

Slide 28 · Fibrinoid necrosis affects decidual vessels

The abnormality is in a maternal vessel wall.

Fibrinoid necrosis is explicitly listed among decidual-vessel changes.

It belongs to the vascular pathology component of the MVM constellation.

Do not confuse this lesion with villous vascular thrombosis on the fetal side.

Slide 29 · Acute atherosis is intimal lipid deposition

A specific form of decidual arterial pathology.

Intimal lipid deposition in decidual vessels is termed “acute atherosis.”

It is listed among abnormal decidual vessels in preeclampsia-related MVM.

Its diagnostic location is the decidual arterial compartment—not fetal villous capillaries.

Slide 30 · Decidual pathology versus villous pathology

Maternal vessel compartment

Villous exchange compartment

Abnormal spiral-artery remodeling

Decidual arterial thrombi

Fibrinoid necrosis

Acute atherosis

Increased syncytial knots

Small, shrunken distal villi

Expanded intervening maternal vascular space

Placental tissue infarcts

Slide 31 · Villous ischemic changes: A schematic contrast

Ordinary terminal villus

Ischemic distal villus

Fetal capillaries

Smaller villus + syncytial knots

The drawing explains features—not diagnostic thresholds or specimen appearance.

Original schematic — not a histologic specimen

Slide 32 · Increased syncytial knots signal villous stress

Exaggerated knotting forms part of the ischemic villous phenotype.

An exaggerated number of syncytial knots is described in affected chorionic villi.

The finding belongs to a pattern of villous and trophoblastic changes.

Interpret the change together with villous size and maternal placental findings.

Slide 33 · Distal villous hypoplasia changes villous architecture

The microscopic pattern is defined morphologically.

Chorionic villi are smaller and shrunken.

Increased maternal vascular space separates the altered villi.

This combination constitutes distal villous hypoplasia.

Slide 34 · Villous underdevelopment reduces exchange architecture

Maternal underperfusion

Villous ischemic response

Small distal villi + increased knots

Altered placental exchange architecture

The final relationship is conceptual: A structural consequence, not a measured exchange-rate claim.

Slide 35 · Placental hypoplasia is not distal villous hypoplasia

Placental hypoplasia

Distal villous hypoplasia

Whole-organ assessment

Placental weight below 10th percentile for gestational age

Gross organ mass reduced

A component of MVM

Microscopic exchange architecture

Small, shrunken terminal villi

Increased intervillous maternal space

An ischemic villous pattern

Slide 36 · Retroplacental hematoma implicates the maternal interface

Fetal surface / chorionic plate

Maternal surface / decidua

Retroplacental

Hematoma

Compartment schematic — not gross pathology

Slide 37 · Retroplacental hematoma reflects bleeding at the interface

Bleeding and unstable uteroplacental vessels may coexist with MVM.

Retroplacental hematomas may accompany preeclampsia-associated malperfusion.

A retroplacental blood collection is anatomically distinct from villous capillary thrombosis.

Placental abruption is also included among the MVM-associated findings.

Slide 38 · Abruption links maternal bleeding to placental compromise

Uteroplacental vessel instability

Bleeding behind placenta

Retroplacental hematoma

Placental separation / abruption

This simplified relationship explains why a maternal-interface lesion may accompany poor perfusion.

Slide 39 · Recognize lesions by placental compartment

Fetal surface / chorionic plate

Maternal surface / decidua

Infarct

Retroplacental

Hematoma

Compartment schematic — not gross pathology

Slide 40 · Morphologic pattern of maternal vascular malperfusion

Finding

Morphologic feature

Compartment

Placental hypoplasia

Organ weight <10th percentile

Whole placenta

Placental infarcts

Ischemic tissue damage

Placental parenchyma

Decidual vasculopathy

Remodeling failure / thrombi / atherosis

Maternal vessels

Distal villous hypoplasia

Small villi + increased maternal space

Chorionic villi

Retroplacental hematoma

Bleeding at maternal interface

Basal placental surface

Slide 41 · Fetal growth restriction is a major clinical correlate

The fetus depends on sustained placental delivery.

The primary MVM section identifies intrauterine growth restriction at the milder end of its effect spectrum.

Reduced maternal intervillous supply provides the pathophysiologic link.

Placental pathology and fetal growth information should be interpreted together.

Slide 42 · Clinical consequence: A fetoplacental sequence

Impaired maternal inflow

Reduced placental exchange reserve

Restricted fetal growth

Possible severe fetal compromise

Source supports fetal growth restriction and severe uteroplacental ischemia; Severity is variable.

Slide 43 · Preeclampsia is an associated maternal syndrome

Placental perfusion and systemic maternal effects intersect.

MVM may be associated with severe uteroplacental ischemia and maternal preeclampsia.

Preeclampsia involves diffuse maternal endothelial dysfunction.

Clinical preeclampsia and morphologic MVM are related—but not synonymous—descriptions.

Slide 44 · Preeclampsia begins with abnormal placentation

Shallow trophoblast invasion

Failed spiral-artery remodeling

Placental ischemia

Maternal endothelial dysfunction

The placenta-centered sequence is presented by Robbins as the principal pathophysiologic model.

Slide 45 · Placental antiangiogenic factors link placenta to mother

The source describes a proposed mediator mechanism.

Ischemic placental tissue is proposed to release factors into maternal circulation.

SFlt-1 antagonizes vascular endothelial growth factor (VEGF) signaling.

Soluble endoglin antagonizes transforming growth factor-β (TGF-β) signaling.

Together these pathways are implicated in systemic endothelial dysfunction.

Slide 46 · Antagonism of VEGF and TGF-β is mechanistically important

Placental ischemic response

Increased sFlt-1 / soluble endoglin

Reduced angiogenic signaling

Maternal endothelial dysfunction

This is a proposed pathogenic pathway in preeclampsia, not a stand-alone placental histologic diagnostic test.

Slide 47 · Endoglin can contribute to vasoconstriction

Soluble endoglin

Antagonism of TGF-β

Less endothelial nitric oxide

Systemic vasoconstriction

A mechanistic formulation (“may contribute”), so the arrow is an explanatory model.

Slide 48 · Endothelial dysfunction explains maternal manifestations

Preeclampsia is systemic, despite a placental origin.

Vasoconstriction contributes to maternal hypertension.

Increased endothelial permeability contributes to proteinuria and edema.

Coagulation abnormalities may produce microvascular thrombi and organ injury.

Slide 49 · A thrombotic pathway accompanies endothelial injury

SFlt-1–VEGF antagonism

Reduced endothelial PGI₂

Impaired antithrombotic state

Microvascular thrombosis risk

Decreased prostacyclin (PGI₂) is associated with hypercoagulability in preeclampsia.

Slide 50 · Placental lesion and maternal syndrome are distinct

MVM: Pathology descriptor

Preeclampsia: Clinical syndrome

Pattern of placental and vascular lesions

Hypoplasia, infarcts and villous ischemia

Decidual artery pathology ± hematoma

Interpretation on placental examination

Maternal endothelial dysfunction

Hypertension and systemic manifestations

Can be linked to abnormal placentation

May be accompanied by MVM morphology

Slide 51 · Maternal versus fetal vascular malperfusion

Maternal vascular malperfusion

Fetal vascular malperfusion

Problem originates in maternal inflow.

Intervillous perfusion is impaired.

Findings include infarcts, decidual vasculopathy and ischemic villi.

Fetal growth restriction may result.

Problem involves the fetal-side placental circulation.

Cord obstruction is a major source example.

Villous vascular thrombi and avascular villi are described.

Do not relabel FVM morphology as MVM.

Slide 52 · Umbilical cord obstruction produces a different pathway

True knot / cord compression

Fetal vascular outflow or inflow obstruction

Villous vascular thrombi

Avascular villi with chronic injury

Chronic/intermittent cord obstruction is associated with fetal vascular malperfusion.

Slide 53 · Avascular villi favor a fetal-side vascular process

Location of injured vessels matters.

Avascular villi occur in fetal vascular malperfusion.

Vascular thrombi within fetal villous circulation support the fetal-side pathway.

This differs from shrunken distal villi and maternal arterial lesions emphasized in MVM.

Slide 54 · Nonvascular inflammatory patterns are a different process

MVM-associated pattern

Placental infection pattern

Abnormal maternal vessels

Small ischemic villi and syncytial knots

Infarcts or placental hypoplasia

Possible retroplacental hematoma

Ascending infection may inflame membranes.

Neutrophilic chorioamnionitis is described.

Hematogenous pathogens may produce villitis.

Diagnose inflammatory lesions separately from MVM.

Slide 55 · Placenta previa is an implantation-site disorder

This adjacent topic is assigned to this teaching unit by the source archive.

Placenta implants in the lower uterine segment and may cover the cervix.

Its defining mechanism is abnormal location, not simply maternal arterial underperfusion.

Severe bleeding in late pregnancy is a key clinical consequence.

Slide 56 · Placenta accreta spectrum is an attachment disorder

Defective decidua changes the villus–myometrium interface.

Absence of decidua allows villi to contact or invade myometrium.

Failure of placental separation at delivery can cause major postpartum hemorrhage.

It should not be equated with MVM simply because both involve abnormal implantation.

Slide 57 · MVM, previa and accreta answer different questions

Primary abnormality

Dominant pathologic/clinical signal

MVM: Maternal circulation cannot supply intervillous space adequately.

Previa: Low uterine implantation in relation to cervix.

Accreta spectrum: Focal/complete decidual absence with adherent or invasive villi.

MVM: Ischemic placental and decidual vascular lesions.

Previa: Potentially serious antepartum hemorrhage.

Accreta: Failure to separate and postpartum hemorrhage.

Slide 58 · Applied case: A small placenta

A placenta from a growth-restricted pregnancy weighs below the gestational-age 10th percentile. Examination also identifies infarcts and small distal villi.

Which maternal-perfusion pattern best integrates these findings?

Hypothetical teaching case

Slide 59 · Case interpretation: Multiple MVM features

Interpretation

Placental hypoplasia is defined relative to gestational age.

Infarcts and small distal villi are additional MVM-associated lesions.

A pattern-based MVM interpretation is stronger than a conclusion from weight alone.

Slide 60 · Applied case: Hypertension and decidual vessels

A pregnancy is complicated by maternal hypertension. The placenta has numerous infarcts; Decidual arteries demonstrate persistent muscular walls and intimal lipid deposition.

Which pathophysiologic link explains this lesion combination?

Hypothetical teaching case

Slide 61 · Case interpretation: Failed arterial remodeling

Interpretation

Persistence of muscular spiral arteries indicates impaired physiologic remodeling.

Intimal lipid deposition is termed acute atherosis.

Reduced uteroplacental perfusion connects vascular pathology to ischemic placental lesions.

Slide 62 · Applied case: Obstruction of a cord vessel

A tightly constricting umbilical-cord knot accompanies placental villous vascular thrombi and avascular villi.

Is this a maternal or fetal vascular malperfusion pattern?

Hypothetical teaching case

Slide 63 · Case interpretation: Fetal vascular malperfusion

Interpretation

The umbilical-cord lesion obstructs the fetal circulation.

Villous vascular thrombi and avascular villi are described FVM findings.

Do not classify these lesions as MVM solely because both can impair fetal growth.

Slide 64 · Applied case: Severe bleeding at delivery

Following prior uterine surgery, the placenta does not separate; Chorionic villi directly contact the myometrium where decidua is absent.

Which placental disorder is illustrated, and why is it not MVM?

Hypothetical teaching case

Slide 65 · Case interpretation: Placenta accreta spectrum

Interpretation

The principal defect is absence of decidua with villous attachment to myometrium.

Placental separation fails, producing a risk of major postpartum hemorrhage.

This is a decidual attachment disorder, not the definition of maternal intervillous underperfusion.

Slide 66 · Approach to an MVM-pattern placenta

Use morphology, compartment and context.

First: Assess placental size relative to gestational age.

Second: Identify infarcts and ischemic villous alterations.

Third: Inspect decidual vessels and the retroplacental interface.

Finally: Correlate with fetal growth, maternal disease and obstetric events.

Slide 67 · Diagnostic pitfalls and safeguards

Avoid collapsing unlike pathologic patterns into one label.

No single listed MVM lesion is obligatory in the Robbins definition.

Placental weight requires a gestational-age reference.

Avascular villi from cord obstruction indicate the fetal circulation.

MVM morphology and maternal preeclampsia are related, not interchangeable diagnoses.

Previa or accreta should be classified by their own defining abnormalities.

Slide 68 · Core principles to retain

Five linked statements summarize the lecture.

MVM = inadequate maternal supply to intervillous placental blood spaces.

Abnormal spiral-artery remodeling is a major pathophysiologic link.

Hypoplasia, infarcts, vascular lesions and villous ischemia constitute a pattern.

Fetal growth restriction and maternal preeclampsia are important associations.

Fetal-side thrombi/avascular villi and implantation disorders require separate classification.

Slide 69 · Source and reading

Primary textbook

Robbins, Cotran & Kumar: Pathologic Basis of Disease. 11th ed. Chapter 22, The Female Genital Tract; pp. 934–939.

Focus

Maternal Vascular Malperfusion; placental anatomy and gestational context; associated preeclampsia pathology. Abnormalities of Placental Implantation are included as distinct related entities.

Diagrams in this presentation are editable teaching schematics, not diagnostic images.