22: Multifetal Gestation and Malpresentation Flashcards
Dizygotic (fraternal) twins
2 separate ova fertilized by 2 separate sperm
each has own amnion, chorion, and placenta
Monozygotic (identical) twins
Arise from cleavage of single fertilized ovum
Dichorionic, diamniotic MZ twins
Cleavage of ovum in 0-3 days
Monochorionic, diamniotic MZ twins
Cleavage of ovum in 4-8 days
Monochorionic, monoamniotic MZ twins
Cleavage of ovum in 9-12 days
Conjoined twins
Cleave of ovum >13 days
Results secondary to uncompensated arterial-venous anastomoses in monochorionic placenta; transfer of blood flow going from one twin to the other
Twin Twin Transfusion Syndrome (TTTS)
Under what condition do you see an acardiac twin?
arterial to arterial anastomoses
Retained Dead Fetus Syndrome
Develops at 20 weeks gestation or greater; can cause DIC. Less than 12 weeks = vanishing twin syndrome; more than 12 weeks = fetus papyraceus
Why should monoamniotic twins be delivered at 32 weeks?
Secondary to increase risk for lethal cord entaglement
Management of delivery in twins?
Vertex-vertex can be managed like singletons
Vertex-transverse, vertex-breech can be delivered vaginally but often delivered C-section
Breech-breech, breech-vertex ALWAYS C-section
Most common fetal malpresentation?
Breech
Most common factor associated with breech presentation?
Prematurity
Most common subtype of breech presentation
Frank (65%) - thighs flexed, LE extended at knees
External Cephalic Version (ECV)
Applying pressure to mom’s abdomen to turn fetus into a forward/backward somersault to achieve vertex position
36 wks gestation, NOT in labor
