Placenta Flashcards
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
What is the earliest the placenta is seen on US
Week 12
Major functioning unit of placenta
Chorionic Villi
Functions
Protection, nutrition, respiration, excretion
Cord should insert
Centrally
May ID by 8-10 wks as
Focal thickening
Size
< or = 5 cm
Visualize retroplacental complex by
18 wks
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.
Grade 3 < 34 wks inc risk for
IUGR, preeclampsia
Grade/calcification delay with, accelerated with
Maternal diabetes, Rh blood
HTN, IUGR, smoking, AMA
Bilobate placenta
2 lobes both equal in size. Cord inserts between both lobes.
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.
Annular placenta
Doughnut, ring shape
Placenta membranacea
Covers surface of sac, very thin.
Placenta Diffusa: rare, covers most of uterine wall.
Circumvallate placenta
Placenta extends beyond chorionic plate. Curled up margins.
Assoc with bleeding and preterm.
Synechiae
Amniotic sheets/folds, thick band with color flow
Amniotic band syndrome/ ADAM complex
Rare, thin membrane of amnion freely cross sac. May entangle fetus. Risk of ABS with early amniocentesis
Placenta size increase with
Diabetes, Rh, CMV, chorioangioma, abruption, twins, hydrops, fetal anemia, triploidy, maternal anemia
Placental size decrease
IUGR, preeclampsia, infarction, toxemia, maternal cardio renal disease, trisomies, severe diabetes, chronic infection, htn
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
Trophotropism
Hypertrophy of upper part & atrophy of lower part bc LUS isn’t as vascular
Vasa Previa
Vessels overly internal os. High fetal mortality. C section.
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
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
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
Teratoma
Rare, usually benign, malignant very bad, complex mass with shadow.
Mets to placenta
From mom: Melanoma, Breast cancer, lung cancer. Lung most common.
Fetal: neuroblastoma, leukemia
Umbilical cord
2 arteries, 1 vein. Mickey Mouse, surrounded by Wharton’s Jelly for protection.
Length: 55cm at term.
Should insert centrally
Marginal cord insertion / battledore placenta
Inserts within 2 cm of edge of placenta. (Inside placenta)
Velamentous insertion
Cord inserts a distance away from placenta (cord inserts on membrane)
Knotted cord
Difficult to ID, hazardous if construction occurs.
Nuchal Cord
Cord around fetal neck, 20% of deliveries. Nurse unwraps cord when delivering.
Cord prolapse
Part of cord presents before fetus. May compromise circulation. Dangerous at birth.
Single Umbilical Artery / 2 Vessel Cord
1 artery at bladder. Mickey Mouse missing ear trvs.
Inc risk IUGR, tri 18, 13, 21
Hemangioma
Benign vascular hyperechoic umbilical cord mass
Teratoma
Ca+. Umbilical cord teratoma.
