Ch. 20 Multiple Gestations

Question 1

Multiple gestations that occur from one fertilized ovum (zygote) are referred to as ——. Multiple gestations that occur when two ova are fertilized (two zygotes) are called —–.

Answer 1

Monozygotic, dizygotic

Question 2

Fraternal twins, occur when two ova are fertilized by two sperm, genders may be same or different

Answer 2

Dizygotic twins

Question 3

How many chorions, amnions and placentas are found in a dizygotic pregnancy

Answer 3

Two chorions, two amnions, two placentas

Question 4

Sono finds of dizygotic twins

Answer 4

confirmed by fetuses with different genders
two chorions
two placentas (may be fused)
two amnions
“twin peak sign” aka “lambda sign”
two yolk sacs

Question 5

Type of twins in which identical fetuses arise from a single fertilized ovum, these twins are always the same gender

Answer 5

Monozygotic twins

Question 6

What sign is seen on the membrane in a monozygotic pregnancy

Answer 6

“T sign”

Question 7

Sono finds of a monochorionic diamniotic gestation

Answer 7

2 separate sacs
1 placenta
thin membrane with “T sign”
2 yolk sacs

Question 8

Sono finds of monochorionic monoamniotic twins

Answer 8

1 sac
1 placenta
1 yolk sac

Question 9

If the embryonic disk divides after —- days gestation, there will be conjoined twins

Answer 9

after 13 days

Question 10

If the morula divides during the first four days of gestation, what type of twins will occur?

Answer 10

Dichorionic diamniotic

Question 11

If the blastocyst splits during the first week of gestation, what type of twins will occur?

Answer 11

Monochorionic diamniotic

Question 12

If the blastocyst splits during the second week of gestation, what type of twins will occur?

Answer 12

Monochorionic monoamniotic

Question 13

List clinical findings of multiple gestations

Answer 13

Increased hCG
increased MS-AFP
increased uterine size (“large for dates”

Question 14

What maternal complications may arise during a twin pregnancy

Answer 14

HTN
Preeclampsia/eclampsia
placental abruption
postpartum hemorrhage
preterm labor and or delivery
anemia

Question 15

What fetal complications are more likely to occur in a twin pregnancy

Answer 15

Prolapse, entanglement, or compression of an umbilical cord
cord knots in monoamniotic twins
difficult delivery due to abnormal positions
IUGR due to plac insufficiency
hypoxia
increased risk of fetal anomalies

Question 16

Complication of a twin pregnancy in which there is a demise of a co-twin causing the maternal body to reabsorb the embryo/fetus and sac.

Answer 16

“Vanishing twin”

Question 17

Twin to twin transfusion syndrome aka Poly-oli sequence occurs in which kind of twins

Answer 17

Monozygotic twins with monochorionic placentation

Question 18

T or F, TTTS has a high mortality rate for the donor twin only, the recipient twin will be okay

Answer 18

False. TTTS has a high mortality rate for both donor and recipient twin alike

Question 19

List treatment options for Poly-oli sequence

Answer 19

Amnioreduction
fetoscopic laser photocoagulation of chorionic plate vessels
(laser off the shared vessels)

Question 20

Sono finds of TTTS in regards to weight and AC

Answer 20

20% difference in fetal weights or AC difference of >20mm

Question 21

Sono finds of TTTS for the recipient twin

Answer 21

Poly
edema and hydrops
large for dates with enlarged viscera

Question 22

Sono finds of TTTS for the donor twin

Answer 22

Oligo
small for dates
“STUCK TWIN” phenomenon: donor fetus positioned in severely oligo sac, causing it to be immobile

Question 23

what does TAPS stand for

Answer 23

Twin-anemia - polycythemia sequence

Question 24

What is TAPS

Answer 24

A form of TTTS with AV anastomoses at the placental edge which allows slow transfusion of blood from the donor to the recipient. There will be highly discordant hemaglobin concentrations at birth. DONOR IS ANEMIC.

Question 25

When does TAPS most likely occur

Answer 25

After laser treatment for TTTS

Question 26

How will amniotic fluid in TAPS be affected and what doppler is the most crucial in diagnosing TAPS

Answer 26

normal amniotic volumes
MCA doppler is crucial in diagnosis

Question 27

The passage of thromboplastic material or blood clots from a dead monochorionic twin to the remaining live twin through shared intraplacenta vasculature

Answer 27

Twin embolization syndrome

Question 28

Sono finds of twin embolization syndrome

Answer 28

intrauterine death of the co-fetus
hydrops
poly
enlarged echogenic kidneys
GI or GU deficits

Question 29

A form of mono mono twinning in which there is an acardiac twin aka holoacardius; “monster”) that has no direct connection with the placenta

Answer 29

Acardiac twinning / parabiotic twin / twin reversed arterial perfusion (TRAP sequence)

Question 30

Sono finds of the acardiac twin in TRAP sequence

Answer 30

multiple structural anomalies
no cardiac motion
may move and grow
anencephaly or small head
cystic hygroma

Question 31

Sono finds of the Pump aka donor twin in TRAP sequence

Answer 31

hydrops fetalis
usually sonographically normal except for cardiomegaly due to increased output
may develop heart failure and hydrops due to cardiac burden

Question 32

Occurs when there is oncomplete division of the embryonic disk after 13 days gestation

Answer 32

Conjoined twins

Question 33

Conjoined twins at the thorax (most common)

Answer 33

Thoracopagus

Question 34

Conjoined twins at the liver, possibly intestines, abd wall

Answer 34

omphalopagus

Question 35

Conjoined twins at the sacrum

Answer 35

pyopagus

Question 36

Conjoined twins at the ischium/pelvis

Answer 36

Ischiopagus