Chapter 27.

Abnormalities of the Placenta, Umbilical Cord and Membranes

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Williams Obstertics, twenty- second edition - page 619 ~ 630 -

 Placental Abnormalities  Abnormalities of the Membranes  Umbilical cord Abnormalities  Pathological Examination

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Placental Abnormalities
 Abnormal Shape or Implantation  Degenerative Placental Lesions  Circulatory Disturbances  Hypertropic Placental Abnormalities  Placental Inflammation  Tumors of the Placenta
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Placental Abnormalities
 Normal placenta (term placenta )  diameter : 22 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 -Heinonen and colleagues, 2001-

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Placental Abnormalities

Multiple Placentas with a single fetus

Abnormal Shape or ImplantationImplantationDefinition  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.  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% Clinical significance

Abnormality

Bilobed placenta

Succenturiate lobes

 retained in the uterus after delivery and may cause serious hemorrhage  accompanying vasa previa - dangerous fetal hemorrhage at delivery

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Placental Abnormalities - Abnormal Shape or ImplantationImplantationAbnormality Membranaceous Placenta Definition  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  Placenta is annular in shape and sometimes a complete ing 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 Clinical significance serious hemorrhage d/t associated placenta previa or accreta

Ring shaped Placenta

Antepartum & postpartum bleeding and fetal growth restriction

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Placental Abnormalities - Abnormal Shape or ImplantationImplantationDiagnosis Fenestrated Placenta Definition Clinical significance

 Central portion of a discoidal placenta mistakenly considered to indicate that a missing is missing portion of placenta  In some instances, there is an actual hole in the placenta but more often the defect involves only villous tissue with the chorionic plate  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

Placenta Accreta Increta Percreta

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Abnormality Extrachorial Placentation

Definition  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

Clinical significance

 Circumvallate Placenta

 Antepartum hemorrhage - from placental abruption and fetal hemorrhage  Preterm delivery  Perinatal mortaliy  Fetal malformations

Circummarginate placenta  Ring dose not have the central depression  less well defined with the fold of membranes www.realpt.co.kr

Placental Abnormalities
- Degenerative Placental Lesions -

 Causes : trophoblast aging or impairment of uteroplacental circulation with infarction  Deposition of calcium salts is heaviest on the maternal surface in the basal plate. further deposition occurs along the septa and both increase as pregnancy progresses  Calcification : 10 - 15% of all placentas at term * By GA33wks : some degree of calcification of placentas
- Spirt and colleagues ,1982 -

 Diagnosis : Sonography
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Placental Abnormalities

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Placental calcification

Placental Abnormalities
- Circulatory Disturbances-

 Placental perfusion may be impaired by disruption of uterine vessels, placental vessels or the intervillous space

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Placental Abnormalities
- Circulatory DisturbancesPlacental infarctions  m/c placental lesions  Etiology : continuum from normal changes to extensive and pathological involvement  Incidence : 10% of 500 consecutive placentas from uncomplicated term pregnancies  Several types (by lesion sites ) - located at the placental margin (90%) , size <1cm(90%) - underneath the chorionic plate - Subchorionic infarct : downward with their apices the intervillous space - Intercotyledonary septa : meet and form a column of cartilage like material extending from the maternal surface to the fetal surface
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Placental infarction
A: placental infarction, B: fibrin deposit, C: normal placenta

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Placental Abnormalities
- Circulatory Disturbances Placental margin (90%) sites cause finding Placental margin occlusion of the maternal uteroplacental circulation normal aging around the edge of nearly every term placental : dense yellowish-white fibrous ring representing a zone of degeneration and necrosis - incidental finding  normal  numerous development of placental insufficiency  thick, centrally located and randomly distributed : preeclampsia or lutus anticoagulant  these conspicuous lesions arise after occlusion of decidual artery interrupts blood flow to the intervillous space : necrosis of villous tissue develops from ischemia  decidual a. occlusion : placental abruption Fibrinoid degeneration of the trophoblast, calcification and ischemic infarction

Associated Lesion

Histopathologic feature www.realpt.co.kr

Placental Abnormalities
- Circulatory DisturbancesMateral Floor infarction  Uncommon lesion  Incidence : 6/1000 deliveries - by Adams-Chapman and colleagues, 2002 Etiopathogenesis : not well defined associated with thrombophilia (in some cases)  Sites : not large areas of villous infarction massive net-like fibrin deposition throughout the placenta
Benirschke and Kaufmann , 2000 -

 Fibroid deposition occurs within the decidua basalis (usually confined to the placental floor) fibrin can extend into the intervillous space to envelop the villi which then atrophy  associated outcome : fetal restriction, abortion , stillbirths, increased incidence of CNS injury and neurodevelopmental sequelae in these infants www.realpt.co.kr not associated with preeclampsia, placental abruption

Placental Abnormalities
- Circulatory DisturbancesPlacental Vessel Thrombosis  When a stem artery from the fetal circulation in the placenta is occluded, it produces a sharply demarcated area of avascularity  Single a thrombosis : 5% of placentas in normal pregnancies 10% of diabetic woman  Thrombosis of a single stem artery will deprive only 5% of the villi of their blood supply  associated with fetal growth restriction and stillbirth
- Benirschke and Kaufmann, 2000 -

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Placental Abnormalities
- Hypertrophic Lesions of the chorionic villi -

 skriking enlargement of the chorionic villi is commonly seen in association with  severe erythroblastosis  fetal hydrops.  maternal diabetes  fetal CHF  maternal-fetal syphilis

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Placental Abnormalities
- Microscopic Placental Abnormalities -

 Syncytial knots: clumps of syncytial nuclei are found to project into the intervillous space - begining after 32wks  The number of cytotrophoblastic cells becomes progressively reduced as pregnancy advances.  By term, such cells are few and inconspicuous  In some maternal or fetal disorders, numerous cytotrophobalstic cells are found in placentas - Gestational hypertension , diabetes and erythroblastosis fetalis

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Placental Abnormalities
-Placental InflammationInflammation-

 Changes that are now recognized as various forms of degeneration and necrosis were formerly described under the term placentitis e.g.) Small placental cysts with grumous contents were formerly thought to be abscesses.  Nonetheless, especially in cases of preterm and prolonged membrane rupture, bacteria invade the fetal surface of the placenta chorioamnionitis

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Placental Abnormalities
-Tumors of the PlacentaPlacenta-

 Gestational Trophoblastic Disease  Chorioangioma(Hemangioma)  Tumors Metastatic to the Placenta  Embolic Fetal Brain Tissue

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Placental Abnormalities
-Tumors of the PlacentaPlacentaChorioangioma (Hemangioma)  The resemblance components to the blood vessels and stroma of the chrionic villus  Benign tumors of placenta  Incidence : 1%  Hamartomas of primitive chorionic mesenchyme  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
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Chorioangioma (Hemangioma)

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Placental Abnormalities
-Tumors of the PlacentaPlacenta Siller and Skafish (1986 ) : Multiple placental chorioangiomas in which a blood group A fetus bleed acutely into her O group mother The mother showed evidence of acute hemolysis without anemia and the fetus developed a sinusoidal heart rate pattern frequently seen with we severe anemia  Severe iron deficiency anemia in the neonate as the consequence of chronic fetal-to-maternal bleeding from multiple small chorioangiomas  Large tumors provide an arteriovenous shunt that can lead to fetal heart failure
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Placental Abnormalities
-Tumors of the PlacentaPlacentaTumor Metastatic to the Placenta  Malignant tumors rarely metastasize to the placenta  Melanoma (1/3), leukemias and lymphomas 1/3  Tumor cells usually are confined within the intervillous space - the fetus : metastases ()  Malignant cells seldom proliferate to cause clinical disease Embolic Fetal Brain Tissue  Fetal brain tissue occasionally is seen embolized to the placenta or fetal lungs  Usually has been described with traumatic deliveries  This phenomenon is not without precedent because brain tissue has been found in pulmonary veins following head trauma in older children and adults
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Abnormalities of the Membranes

 Meconium Staining  Chorioamnionitis  Other Abnormalities

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Abnormalities of the Membranes

- Meconium Staining  Incidence : remarkably constant 20% of almost 250,000women delivered during the past 20years - in Parkland Hospital  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 Benirschke and Kaufmann(2000)

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Abnormalities of the Membranes

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

Abnormalities of the Membranes

- Meconium Staining  Clinical significance : perinatal morbidity and mortality - by Nathan and co-workers in Parkland Hospital, 1994- perinatal mortality - 1.5 : 0.3 per 1000 - severe fetal acidemia (cord arterial pH < 7.0) - 7 : 3 per 1000 - cesarean delivery : doubled (14% : 7%) : 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
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Abnormalities of the Membranes

- Chorioamnionitis Imflammation of the fetal membranes is usually manifestation of imtrauterine infection  Associated with prolonged membrane rupture and long labor  Characteristic : clouding of the membranes foul odor (depending on bacterial species and concentaraion )  Definition : mono-and polymorphonuclear leukocytes infiltrate the chorion, the resulting microscopical finding - cells origin : maternal  Leudocytes are found in amnionic fluid (amnionitis) or the umbilical cord(funisitis) - cell origin : fetus  < 20 wks almost all polymorphonuclear leukocytes : maternal origin > 20 wks: Inflammatory response : maternal & fetal  Preterm deliveries : m/c
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Abnormalities of the Membranes

- Chorioamnionitis  Accordign to some investigators these findings of inflammation may be nonspecific and are not always associated with other evidence of fetal or maternal infection  Management : antimicrobial administration and expedient delivery  Explanation for many otherwise unexplained cases of ruptured membaranes, preterm labor or both
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Abnormalities of the Membranes

-Other AbnormalitiesAbnormalities Amnionic cyst Definition & causes  lined by typical amnionic epithelium  fusion of amnionic folds with subsequent fluid retention  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  Intrauterine amputation Clinical significance

Amnion nodosum

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

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Umbilical Cord Abnormalities

         Length Cord Coiling Single Umbilical Artery Four-vessel cord Abnormalities of cord insertion Cord Abnormalities capable of impeding blood flow Torsion and Strictures Hematoma Cysts

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Umbilical Cord Abnormalities

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

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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) - Krakowiak and associates,2004  Excessively long cords : associated with - maternal systemic disease and delivery complications such as prolapse, cord entanglement, fetal distress, fetal anomalies and respiratory distress - perinatal mortality : increased nearly threefold, albeit with borderline statistical significance
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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

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Long cord

Short cord

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 in one with hypercoiled cords
- Rana and associates (1995) -

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Umbilical Cord Abnormalities

Single Umbilical Artery
 The umbilical cord : typically contains two arteries and a single vein  Risk factors : in women with diabetes, epilepsy, preeclampsia, antepartum hemorrhage, oligohydramnios and hydramnios increased incidence  of all infants with only 1artery have associated congenital anomalies - two-vessel cords were identified in 1.5% of 879 fetuses aborted spontaneously : serious malformation, most associate with chromosomal abnormalities >1/2 of these - Byrne and Blane,1985www.realpt.co.kr

Umbilical Cord Abnormalities

Single Umbilical Artery
 Diagnosis : routine ultrasound screening - GA 17~36wks : 98% of cases  Prognosis - fetal prognosis : depends on whether the two-vessel cord is associated with other abnormalities or whether it is an isolated finding - Perinatal prognosis : two-vessel umbilical cord is an isolated sonographic finding better
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Umbilical Cord Abnormalities

Single Umbilical Artery
 Budorick and co-workers (1995) : no abnormal karyotypes and only one echocardiographic abnormality in 31 fetuses with a two-vessel cord  Gossett and associates (2002) : 74 such fetuses all had normal echocardiography  Catanzarite (1995) - two of 46 fetuses : lethal chromosomal abnormalities - 1/3 of 46 fetuses : tracheoesophageal fisrula

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Umbilical Cord Abnormalities

Single Umbilical Artery
 When a two vessel cord is a nonisolated finding - aneuploid - Budorick and associates (2001) - renal aplasia, limb-reduction defects, atresia of hollow organs in such fetuses, suggesting a vascular etiology
- Pavlopoulos and colleagues (1998)

 Goldkrand and associates (2001) : growth restriction did not occur in anatomically normal fetus with a single artery

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Umbilical Cord Abnormalities Four vessel cord

 Venous remnant in 5%  Significance : unknown

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Umbilical Cord Abnormalities

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

Anomalities Furcate insertion Definition
Umbilical vessels separate from the cord substance before their insertion into the placenta

incidence Rare

Significance

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

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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 - : associated with velamentous inserion - : marginal cord insertions and bilobedor, succenturiate-lobed placentas  Risk factors - bilobed , succenturiate or low-lying placenta - Multifetal pregnancy - Pregnancy resulting from in vitro fertilization
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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%
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Umbilical Cord Abnormalities

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

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False knot(Lt), true knot (Rt)

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%

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Umbilical Cord Abnormalities

Cord Abnormalities capable of impeding blood flow
 coiling of the cord around the neck is an uncommon cause of antepartum fetal death or neurological damage  Entwined cords cause intrapartum complications  As labor progresses and there is fetal descent, contractions may compress the cord vessels fetal heart rate deceleration that persist until the contraction ceases  In labor 20% of fetuses with a nuchal cord have moderate to severe valiable heart rate deceleration have a lower umbilical artery pH
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Umbilical Cord Abnormalities

Torsion and Strictures
Torsion  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
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Umbilical Cord Abnormalities

Hematoma

 accumulations of blood are associated with short cords, trauma and entanglement  result from the rupture of a varix, usually of the umbilical vein with effusion of blood into the cord  caused by umbilical vessel venipuncture

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Umbilical Cord Abnormalities

Cysts
: found along the course of the cord and are designate true and false according to their origin
True Size Small Considerable size Result from liquefaction of Wharton jelly false

Causes Derived from remnants of the umbilical vesicle or the allantois

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Pathological Examination

 Placenta and cord including the number of vesselsshould be examined grossly following all deliveries  Decision to request pathological examination will depend on clinical and placental findings

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Pathological Examination
 Pathological placental examination in the following circumstances  Perinatal death  Preterm delivery  Fetal growth abnormalities  Fetal malformations  Hydrops  Any other fetal disorders  Multiple pregnancy  Maternal disorders  Gross placental lesions
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Placental Abnormalities
- Abnormal Shape or ImplantationImplantation-

Circumvallate(left) and cricummarginate(right) variaties of extrachorial placentas

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Placental Abnormalities
- Abnormal Shape or ImplantationImplantation-

Anomaly of Placental site www.realpt.co.kr

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Velamentous Insertion

Vasa previa

Internal cx os

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