Multifetal Gestation and Malpresentation Flashcards
dizygotic twins
-when two separate ova are fertilized by two separate sperm
monozygotic twin (identical)
-arise from the cleavage of a single fertilized ovum at various stages during embryogenesis
what is the inner layer of the embryo
the amnion
outer layer?
chorion
what determines what kind of twins there will be?
- time of cleavage:
- 0-3 days: dichorionic, diamniotic
- 4-8 days: monochorionic, diamniotic
- 9-12 days: monochorionic monoamniotic
- > 13 days: conjoined twins
What kind of embryo do most monozygotic twins have?
- monochorionic, diamniotic
- so at least they get SOMETHING to themselves
Which kind is the most dangerous because there are not separating amnions?
- Monochorionic monoamniotic
- cord entanglement happens
how is the hCG in someone who is having twins?
-higher than normal
What is the most important step after diagnosing twins?
determining zygosity
What do you see on U/S for dizygotic?
-inverted V sign at the base of septum
U/S for monozygotic
-dividing membrane is fairly thin
What will help confirm zygosity?
- DNA analysis
- Inspect placenta after delivery
Treatment for TTTS?
- serial amniocentesis with amniotic fluid reduction
- laser photocoagulation of the anastamosis vessels on the placenta is performed at specialized centers
When should monoamniotic twins be delivered?
- 32 weeks
- 38 weeks if no complications
What do we need to be prepared for in vertex-vertex presentations of twin birth?
-postpartum hemorrhage secondary to uterine atony
