Multiple Gestations

Question 1

Twins arising from a single zygote

Answer 1

Monozygotic

Question 2

Twins arising from two separate zygotes

Answer 2

Dizygotic

Question 3

A fertilized egg

Answer 3

Zygote

Question 4

Union of sperm and egg

Answer 4

Fertilization

Question 5

Twins with separate placentas

Answer 5

Dichorionic

Question 6

Twins who share the same amniotic sac

Answer 6

Monoamniotic

Question 7

Most common form of twins

Answer 7

Dizygotic

Question 8

Disygotic twins always result in ___chorionic and ___amniotic

Answer 8

Dichorionic and Diamniotic

Question 9

Twins arising from a single zygote that splits

Answer 9

Monozygotic

Question 10

Splitting of a zygote is termed

Answer 10

Cleavage

Question 11

Most common form of monozygotic twins

Answer 11

Monochorionic and Diamniotic

Question 12

When cleavage happens before day 4:

Answer 12

Dichorionic and Diamniotic

Question 13

When cleavage happens between days 4-8

Answer 13

Monochorionic and Diamniotic

Question 14

Cleavage happens after day 8:

Answer 14

Monochorionic and monoamniotic

Question 15

Least common monozygotic twins:

Answer 15

Monochorionic and monoamniotic

Question 16

Sonographic sign confirming chorionicity in the 2nd/3rd trimesters

Answer 16

Twin peak/lambda/delta sign

Question 17

What sign is this? What does this prove?

Answer 17

Lambda/twin peak/delta sign. Proving dichorionic

Question 18

With Twin to Twin Transfusion Syndrome(TTTS) the twin that shunts blood to the other is called:

Answer 18

Donor twin

Question 19

With TTTS, which twin is smaller?

Answer 19

Donor

Question 20

With TTTS, twin that receives shunted blood:

Answer 20

Recipient

Question 21

Severe oligohydramnios surrounding a twin that appears to be closely associated with the uterine wall

Answer 21

Stuck twin

Question 22

Severe form of TTTS

Answer 22

Acardiac twinning

Question 23

Acardiac twinning aka

Answer 23

Twin-Reversed Arterial Perfusion

Question 24

Abnormal anastomoses of placental vessels in a twin pregnancy

• one normal twin
• one twin is missing the upper body and heart

Answer 24

Acardiac twin

Question 25

The most common forms of conjoined twins:

Answer 25

• thoracopagus—chest

- omphalopagus—stomach

Question 26

Conjoined twins joined at the cranium

Answer 26

Craniopagus

Question 27

Conjoined twins joined at the back

Answer 27

Pyopagus

Question 28

Conjoined twins joined at the pelvis

Answer 28

Ischiopagus

Question 29

The death of a twin and subsequent reabsorption during the fist trimester

Answer 29

vanishing twin

Question 30

Twin dies in first trimester but is not reabsorbed and is maintained throughout the pregnancy

Answer 30

Fetus papyraceus

Question 31

• Death of a monochorionic twin
• vascular products travel from demised twin to the surviving twin
• CNS, kidneys damaged
• hydrocephalus and porencephaly

Answer 31

Twin embolization syndrome

Question 32

During first trimester, DICHORIONIC twins will be separated by:

Answer 32

Thick membrane separating the two amniotic sacs

Question 33

The arrowheads are pointing to what in this 1st trimester scan?

Answer 33

Thick membrane—proves dichorionic

Question 34

Arrowheads are pointing to what in this 1st trimester scan?

Answer 34

No thick membrane—Monochorionic

Arrowheads—Separate amnion for each fetus—Diamniotic

Question 35

Median gestational age of delivery for twins

Answer 35

35 weeks

Question 36

Twins at risk for being conjoined:

Answer 36

Monochorionic Monoamniotic