Flashcards in Placenta Deck (37)
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What is the earliest the placenta is seen on US
Week 12
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Placenta
Vascular organ
Discoid shape
Weighs 500-600 g
Chorionic plate on fetal side
20 lobes
Basilar plate on maternal side adj to retroplacental complex
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Major functioning unit of placenta
Chorionic Villi
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Functions
Protection, nutrition, respiration, excretion
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Cord should insert
Centrally
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May ID by 8-10 wks as
Focal thickening
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Size
< or = 5 cm
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Visualize retroplacental complex by
18 wks
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Grading
0: smooth no Ca+, homo
1: sm Ca+ randomly dispersed
2: Ca+ of basilar plate
3: Ca+ intentions of pl extending from chorionic plate to basilar plate. See lobes.
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Grade 3 < 34 wks inc risk for
IUGR, preeclampsia
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Grade/calcification delay with, accelerated with
Maternal diabetes, Rh blood
HTN, IUGR, smoking, AMA
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Bilobate placenta
2 lobes both equal in size. Cord inserts between both lobes.
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Succentureate Lobe/Accessory Lobe
1 or more small lobes connect to main placenta. If retained after delivery, may hemorrhage. Connecting vessels may overly internal os.
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Annular placenta
Doughnut, ring shape
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Placenta membranacea
Covers surface of sac, very thin.
Placenta Diffusa: rare, covers most of uterine wall.
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Circumvallate placenta
Placenta extends beyond chorionic plate. Curled up margins.
Assoc with bleeding and preterm.
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Synechiae
Amniotic sheets/folds, thick band with color flow
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Amniotic band syndrome/ ADAM complex
Rare, thin membrane of amnion freely cross sac. May entangle fetus. Risk of ABS with early amniocentesis
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Placenta size increase with
Diabetes, Rh, CMV, chorioangioma, abruption, twins, hydrops, fetal anemia, triploidy, maternal anemia
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Placental size decrease
IUGR, preeclampsia, infarction, toxemia, maternal cardio renal disease, trisomies, severe diabetes, chronic infection, htn
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Placenta Previa
Placental covers internal os
Complete/Total: covers both sides of cx canal
Partial/Marginal
Low lying: within 2 cm of io
Do c section
Painless vag bleeding
Inc with AMA, smoking, multiparity, c sections, low ut scars, trauma, hx D&C, twins, abnl fetal lie
Premature delivery, maternal hemorrhage, placenta accreta, post partum hemorrhage, IUGR,
Over distended bladder cause false positive
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Trophotropism
Hypertrophy of upper part & atrophy of lower part bc LUS isn't as vascular
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Vasa Previa
Vessels overly internal os. High fetal mortality. C section.
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Abruption
Premature placenta detachment
Dangerous.
Knife like pain. Bleeding, shock, preterm labor, fetal distress/demise
Assoc with HTN, cocaine, vasc disease, trauma, preeclampsia, short umb cord, fibroids, previa
Hematoma. Retroplacental hemorrhage
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Placenta Accreta
Abnl placental attachment
Accreta: on myometrium, mildest, most common
Percreta: into myometrium
Increta: through serosa, rarest
Hx of c section + previa = 25% chance
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Chorioangioma
MC placental tumor
1%, benign vasc tumor, inc MSAFP, through fetal surface of placenta, solid, complex, usually near cord insert.
Large leads to hydrops, polyhydramnios, hemorrhage, premie, IUGR, demise, cardiomegaly
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Teratoma
Rare, usually benign, malignant very bad, complex mass with shadow.
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Mets to placenta
From mom: Melanoma, Breast cancer, lung cancer. Lung most common.
Fetal: neuroblastoma, leukemia
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Umbilical cord
2 arteries, 1 vein. Mickey Mouse, surrounded by Wharton's Jelly for protection.
Length: 55cm at term.
Should insert centrally
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Marginal cord insertion / battledore placenta
Inserts within 2 cm of edge of placenta. (Inside placenta)
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Velamentous insertion
Cord inserts a distance away from placenta (cord inserts on membrane)
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Knotted cord
Difficult to ID, hazardous if construction occurs.
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Nuchal Cord
Cord around fetal neck, 20% of deliveries. Nurse unwraps cord when delivering.
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Cord prolapse
Part of cord presents before fetus. May compromise circulation. Dangerous at birth.
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Single Umbilical Artery / 2 Vessel Cord
1 artery at bladder. Mickey Mouse missing ear trvs.
Inc risk IUGR, tri 18, 13, 21
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Hemangioma
Benign vascular hyperechoic umbilical cord mass
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