Placenta Flashcards
How does the fertilised egg implant into the uterine wall?
Invasion by trophoblastic cells
What happens to the blastocyst cells?
They become bilaminar and then trilaminar disks
2 main components of the early placenta structure
Villous chorion and smooth chorion
What is the fetal part of the placenta known as?
villous chorion
What is the maternal part of the placenta known as?
Decidua basalis
Where in the placenta does maternal blood flow into?
Intervillous spaces
Which arteries squirt blood into the intervillous space?
spiral arteries
What separates the fetal and maternal circulation
1 layer of trophoblastic cells
What 2 layers extend from the margin of the disk to provide fetal membranes
Amnion and chorion
what is placenta praevia? different forms?
when the implantation occurs late and attaches to the lower part of your womb, can be marginal, complete or low lying
What is placenta accreta?
when the villous tissue buries too deep within the wall even to the serosa
What is placenta percreta?
When the placenta grows through the wall and into the pelvic cavity potentially to other organs in the nearby vicinity
What is a hydatidiform mole? more predisposed to developing what?
No fetus but a large grape like placenta needing HCG mointoring to ensure gets reabsorbed, more predisposed to choriocarcinoma
an abnormality that can occur at the insertion site of the cord? risk of what?
Velamentous (inserts into membranes and not fetal disc) risk of rupture at delivery
What is Vasa Praevia?
When the velamentous cord lies ahead of the babies head on delivery
What can you tell about the cord if the babies head presents with marked effusion?
Cord entanglement stopping venous return to the body
What needs to be assessed in babies with SUA?
renal function
what is chorioamnionitis and how does it usually occur?
Inflammation of the placental membranes usually due to ascending E.coli, bacterial or fungal source from maternal perineum
What crucial organ is effected in oligohydramnios
Lungs undergo pulmonary hypoplasia and insufficient to support life
What deformaties can be caused by oligohydramnios?
Potters sequence (low set ears, receding chin, beaked nose, crease under eyes) club foot
What is amnion nodosum and how does it lead to abnormalities in the placenta?
clusters of pin point spots on the placenta due to oligohydramnios
What can occur if the amnion ruptures but the chorion stays in tact?
part of the baby can pass through the bands and then lead to defects like missing fingers and toes
Circummarginate vs circumvallate placenta?
circummarginate appears dinner plate like with thick outer rim and circumvallate appears grey and whiteish as membranes arise from placental disc and not edges causing haemorrhage and pealing off wall
What is the malformation in a succenturiate placenta form?
Accessory lobe present often with velamentous cord issues
Describe what usually occurs in a retroplacental clot
bleed from spiral artery, emergency delivery, antepartrum haemorrhage, usually area of infarct where clot has restricted blood supply
Chorangioma?
benign tumour of blood vessels like haemangioma
How will CMV infections appear on the placenta?
Deep purple inclusions with a surrounding clear rim
How does a mother usually get parvovirus infection in pregnancy?
Children presenting with slapped cheek and febrile illness
How does parvovirus effect the neonate in utero? why?
Hydrops and IUD, virus causes haemolysis, HF and death
What CV effects on the baby can diabetic mothers have?
Polycythaemia and born with cardiomyopathy
What condition suffered in pregnancy can increase chances of retroplacental haemorrhage?
PIH/essential hypertension
What are monoamniotic-monochorionic twins more susceptible to in comparison to diamniotic-monochorionic twins?
Cord entanglement as they dont have a membrane separating them
What are diamniotic-monochorionic twins more susceptible to in comparison to monoamniotic-monochorionic twins?
TTTS
How is TTTS treated?
Laser ablation
2 types of asymmetrical twinning
siamese and acardiac acephalic
What is fetus papyraceous?
Death in utero of one twin, mummified, born alongside
