Module 13 - Multiple Gestations Flashcards
Most common type of twinning
Dizygotic (70%)
Hereditary on the maternal side
Dizygotic
Fertilization of two separate ova
Dizygotic
Two configurations of dizygotic twins
DC/DA and DC/DA fused
A single fertilized ovum replicates during early development
Monozygotic twins
Twin peak sign
Two placentas, two amniotic sacs
T sign
One placenta, two amnion
Types of monozygotic twin configurations
DC/DA (DI/DI)
MC/DA (Mono/Di)
MC/MA (Mono/Mono)
Conjoined
Incomplete division at embryonic disc stage with no separating membranes
Conjoined twins
Which baby is twin A?
The one closest to the cervix
Arterial-arterial or venous-venous shunts (anastomoses) in the placenta of monochorionic twins
TRAP syndrome (twin reversed arterial perfusion)
Parasitic twin within abdomen of its sibling
Fetus in fetu
A-A, V-V or A-V fistulas in the placenta of monochorionic twins only
Twin to twin transfusion syndrome
Recipient: large, hypertensive, polyhydramnios
Donor: small, hypotensive, oligohydramnios, “stuck” appearance
Twin to twin transfusion donor vs recipient
One baby has little or no fluid and the amniotic membrane holds baby tightly to uterine wall
Stuck twin
Fetal doppler profiles in the umbilical artery
Normal: lots of diastolic flow
Bad: no diastolic flow
Very bad: reversed diastolic flow
Normal wave profile of the ductus venosus
ASVD wave (venous profile)
Clots from a demised twin passed to the surviving twin in monochorionic
twin embolization syndrome
Two ovum fertilized
Dizygotic
Omphlopagus & Thoroacopagus
Most common types of conjoined twins
One normal donor twin profuse the other abnormal twin. Abnormal twin has only lower legs and trunk and now heart of its own.
TRAP syndrome
What size discordance would suggest the beginning of TTTS?
20%
