The Placenta Flashcards
How many arteries and veins does the normal umbilical cord contain?
2 arteries, 1 vein
If a newborn presents with a single umbilical artery, what further investigation should be performed?
Search for congenital anomalies. Consider renal US. Cardiac and urogenital anomalies are common.
How is chorioamnionitis diagnosed?
It’s a clinical diagnosis characterized by maternal fever +/- uterine tenderness, foul-smelling amniotic fluid, and maternal/fetal tachycardia.
Define prolonged rupture of membranes.
rupture >18 hours
Which are the 3 most common bacteria associated with early-onset neonatal sepsis?
GBS, E. coli, and Listeria monocytogenes
Define placental abruption.
Complete or partial placental detachment prior to delivery of the fetus.
Which types of twins have diamniotic, monochorionic placentas?
Monozygotic identical twins, when there is initially only one ovum before division.
Which type of placenta usually occurs with fraternal twins?
Diamniotic, dichorionic
Define placenta accreta
Occurs when the placental villi attach to the myometrium without invading it.
Define placenta increta
Occurs when the placental villi invade the myometrium without penetrating it.
Define placenta percreta
Occurs when the placental villi penetrate the myometrium into the uterine serosa +/- surrounding organs
What is a chorioangioma and how might it affect fetal development?
It’s a benign placental tumor which may interfere with fetal circulation, causing heart failure and hydrops.
Which placental structure is the means by which the fetus receives nutrients, oxygen, and water from the mother, and by which it excretes waste into the maternal blood stream?
The syncytium, which is the outer portion of the placenta that makes direct contact with the mother.
Which is more concerning, a short or a long umbilical cord?
Shorter cords (<40 cm) are rare and can indicate fetal morbidity, such as amniotic bands or neurologic disorders. By contrast, longer cords are common and are not associated with increased risk of morbidity but have the potential to form knots, prolapse, or entwine the fetus.
Describe twin-twin transfusion syndrome.
When an artery from one twin supplies the cotyledon that is then drained by a vein into the other twin, TTTS occurs. One twin develops polycythemia, while the other becomes anemic. This can escalate to heart failure and hydrops in the recipient twin and to decreased amniotic fluid volumes in the donor.
