www.realpt.co.kr
Abnormalities of the Placenta, Umbilical Cord
and Membranes
Williams Obstertics, twenty- second edition
www.realpt.co.kr
Placental Abnormalities
Abnormalities of the Membranes
Umbilical cord Abnormalities
Pathological Examination
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities
Abnormal Shape or Implantation
Degenerative Placental Lesions
Circulatory Disturbances
Hypertropic Placental Abnormalities
Placental Inflammation
Tumors of the Placenta
www.realpt.co.kr
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-
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities- - Abnormal Shape or Implantation-Abnormal Shape or Implantation-
Abnormality Definition Clinical significanceMultiple 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
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities- - Abnormal Shape or Implantation-Abnormal Shape or Implantation-
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 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
Antepartum & postpartum bleeding and fetal growth restriction
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities- - Abnormal Shape or Implantation-Abnormal Shape or Implantation-
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
www.realpt.co.kr
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
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities- Degenerative Placental Lesions -- 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 ≥ ½ of placentas - Spirt and colleagues ,1982 - Diagnosis : Sonography
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities
Placental calcification
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities- Circulatory Disturbances-
Placental perfusion may be impaired by disruption of uterine vessels, placental vessels or the intervillous space
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities- Circulatory Disturbances-
Placental 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
www.realpt.co.kr
Placental infarctionA: placental infarction, B: fibrin deposit, C: normal placenta
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities- Circulatory Disturbances -
Placental margin (90%)sites Placental margin
cause occlusion of the maternal uteroplacental circulation normal aging
finding around the edge of nearly every term placental : dense yellowish-white fibrous ring representing a zone of degeneration and necrosis - incidental finding
Associated Lesion
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
Histopathologic feature
Fibrinoid degeneration of the trophoblast, calcification and ischemic infarction
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities- Circulatory Disturbances-
Materal 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
not associated with preeclampsia, placental abruption
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities- Circulatory Disturbances-
Placental 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 -
www.realpt.co.kr
Placental AbnormalitiesPlacental 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
www.realpt.co.kr
Placental AbnormalitiesPlacental 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
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities-Placental Inflammation--Placental Inflammation-
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
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities-Tumors of the Placenta--Tumors of the Placenta-
Gestational Trophoblastic Disease
Chorioangioma(Hemangioma)
Tumors Metastatic to the Placenta
Embolic Fetal Brain Tissue
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities-Tumors of the Placenta--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% 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
www.realpt.co.kr
Chorioangioma (Hemangioma)
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities-Tumors of the Placenta--Tumors of the Placenta-
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
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities-Tumors of the Placenta--Tumors of the Placenta-
Tumor 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 (¼) 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
www.realpt.co.kr
Abnormalities of the Membranes
Meconium Staining
Chorioamnionitis
Other Abnormalities
www.realpt.co.kr
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)
www.realpt.co.kr
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 19
42 weeks or greater 23
www.realpt.co.kr
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
www.realpt.co.kr
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
www.realpt.co.kr
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
www.realpt.co.kr
Abnormalities of the Membranes-Other Abnormalities-
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
www.realpt.co.kr
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
www.realpt.co.kr
Umbilical Cord Abnormalities
Length
: appreciable variation, extremes range - no cord(achordia) ~ lengths<300cm - mean length : 37cm - excessively long cords : ≥ 70cm ( ≥2 SD )
www.realpt.co.kr
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
www.realpt.co.kr
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
www.realpt.co.kr
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) -
www.realpt.co.kr
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
¼ 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,1985-
www.realpt.co.kr
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
Umbilical Cord Abnormalities Single Umbilical Artery
www.realpt.co.kr
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
www.realpt.co.kr
Umbilical Cord Abnormalities Single Umbilical Artery
When a two vessel cord is a nonisolated finding - aneuploid ≥ ½ - 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
www.realpt.co.kr
Umbilical Cord Abnormalities Four – vessel cord
Venous remnant in 5%
Significance : unknown
www.realpt.co.kr
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
www.realpt.co.kr
Umbilical Cord AbnormalitiesAnomalities 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
www.realpt.co.kr
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
www.realpt.co.kr
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%
www.realpt.co.kr
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 cordTrue 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)
www.realpt.co.kr
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%
www.realpt.co.kr
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
www.realpt.co.kr
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
www.realpt.co.kr
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
www.realpt.co.kr
Umbilical Cord Abnormalities Cysts
True falseSize
Causes
Small
Derived from remnants of the umbilical vesicle or the allantois
Considerable size
Result from liquefaction of Wharton jelly
: found along the course of the cord and are designate true and false according to their origin
www.realpt.co.kr
Pathological Examination
Placenta and cord – including the number of vessels- should be examined grossly following all deliveries
Decision to request pathological examination will depend on clinical and placental findings
www.realpt.co.kr
Pathological Examination
Pathological placental examination in the following circumstances
Perinatal deathPreterm deliveryFetal growth abnormalitiesFetal malformations HydropsAny other fetal disordersMultiple pregnancyMaternal disordersGross placental lesions
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities- Abnormal Shape or Implantation-- Abnormal Shape or Implantation-
Circumvallate(left) and cricummarginate(right) variaties of extrachorial placentas
www.realpt.co.kr
Placental AbnormalitiesPlacental Abnormalities- Abnormal Shape or Implantation-- Abnormal Shape or Implantation-
Anomaly of Placental site
www.realpt.co.krVelamentous Insertion
www.realpt.co.kr
Vasa previa
Internal cx os
Top Related