Class 13: Multiples

Question 1

type of twinning that is fertilized by 1 ovum & 1 sperm, then splits into 2

Answer 1

monozygotic/identical twins

Question 2

percentage of twinning that makes up monozygotic twins?

Answer 2

30%

Question 3

are monozygotic twins hereditary?

Answer 3

no – random

Question 4

monozygotic twins are always the ___ sex & ____ genetic make up

Answer 4

same sex; identical genetic make up

Question 5

type of twinning that is fertilized by 2 ovum & 2 sperm

Answer 5

dizygotic/fraternal twins

Question 6

percentage of twins that make up dizygotic twins

Answer 6

70%

Question 7

dizygotic twins are always the same sex. T/F?

Answer 7

false

Question 8

dizygotic twins have ___ genetic make up

Answer 8

different

Question 9

dizygotic twins always have separate placentas. T/F?

Answer 9

true

Question 10

race with higher incidence of twinning?

Answer 10

black

Question 11

race with the lowest incidence of twinning?

Answer 11

asian

Question 12

age that has a higher incidence of twinning?

Answer 12

older maternal age – 35-39 yo

Question 13

what type of twin is hereditary?

Answer 13

dizygotic twins

Question 14

does the maternal or paternal side carry the genes for twinning?

Answer 14

maternal

Question 15

what type of infertility drugs increases the chance for twinning?

Answer 15

pergonal & clomid

Question 16

2 layers of placental membranes

Answer 16

1. chorion
2. amnion

Question 17

list the types of placentas & membranes

Answer 17

1. dichorionic diamniotic
2. monochorionic diamniotic
3. monochorionic monoamniotic

Question 18

how many placentas & yolk sacs are in a di-di pregnancy?

Answer 18

2 placentas, 2 yolk sacs

Question 19

how many placentas & yolk sacs are in a mo-di pregnancy?

Answer 19

1 placentas & 2 yolk sac

Question 20

how many placentas & yolk sacs are in a mo-mo pregnancy?

Answer 20

1 placenta & 1 yolk sac

Question 21

what type of placentation can dizygotic twins have?

Answer 21

only dichorionic diamniotic

Question 22

what type of placentation can monozygotic twins have?

Answer 22

can have all 3 types depending on when division occurred

Question 23

monozygotic twins must be separated between ____ days after conception for them to have dichorionic diamniotic placentation

Answer 23

0-4 days

Question 24

monozygotic twins must be separated between ____ days after conception for them to have monochorionic diamniotic placentation

Answer 24

4-8 days

Question 25

monozygotic twins must be separated between ____ days after conception for them to have monochorionic monoamniotic placentation

Answer 25

8-13 days

Question 26

incomplete separation occurs if monozygotic twins haven't separated after ____ days after conception. this is also called ____

Answer 26

13 days; conjoined twinning

Question 27

which type of placentation exhibits a twin peak/lambda sign?

Answer 27

dichorionic diamniotic

Question 28

which type of placentation exhibits a T-sign?

Answer 28

monochorionic diamniotic

Question 29

which fetus would you label "fetus A" on U/S?

Answer 29

the presenting fetus (closest to cervix)

Question 30

4 types of twin abnormalities?

Answer 30

1. vanishing twin syndrome 2. fetus papyraceus 3. conjoined twinning 4. fetus in fetu

Question 31

what is vanishing twin syndrome?

Answer 31

seeing twin gestation early in pregnancy but only having a singleton at birth

Question 32

what can be the etiology for vanishing twin syndrome?

Answer 32

one gestation was an anembryonic or nonviable pregnancy & was able to be reabsorbed

Question 33

US appearance of vanishing twin syndrome

Answer 33

- GS smaller than other according to LMP - GS with irregular borders - GS crescent-shaped with incomplete trophoblastic ring

Question 34

what is fetus papyraceus?

Answer 34

when a dead fetus is too large to be reabsorbed and is preserved in a distorted shape

Question 35

during which trimester(s) of pregnancy can fetus papyraceus occur?

Answer 35

2nd or 3rd tri

Question 36

what is a probable cause for fetus papyraceus?

Answer 36

polyhydramnios of larger twin compresses smaller twin

Question 37

what type of pregnancy & placentation can fetus papyraceus occur in?

Answer 37

monozygotic pregnancy with monochorionic diamniotic placentation

Question 38

what is the most common type of abnormal twinning?

Answer 38

conjoined twins

Question 39

what type of pregnancy and placentation can conjoined twinning occur in?

Answer 39

monozygotic pregnancy with monochorionic monoamniotic placentation

Question 40

conjoined twins can be different sexes

Answer 40

false

Question 41

conjoined twins are 70% male

Answer 41

false -- 70% female

Question 42

how does conjoined twinning occur?

Answer 42

if division of ovum occurs after 13 days from conception

Question 43

what is the most common type of conjoined twinning?

Answer 43

thoracopagus

Question 44

what is fetus in fetu?

Answer 44

a rare type of conjoined twinning where one twin is in the body of co-twin

Question 45

where is the location of the parasitic twin in fetus in fetu?

Answer 45

typically in upper retroperitoneum of co-twin; usually seen as an abdominal mass

Question 46

differential diagnosis of fetus in fetu?

Answer 46

teratoma

Question 47

U/S appearance of fetus in fetu?

Answer 47

complex mass in abdomen

Question 48

what does PROM stand for?

Answer 48

premature rupture of membranes

Question 49

what is the most common complication in the 3rd trimester for multiple gestations?

Answer 49

premature labor with PROM

Question 50

what is the cause of premature labor with PROM?

Answer 50

overdistension of uterus

Question 51

some complications associated with premature labor with PROM?

Answer 51

- bleeding due to increase risk for placenta previa, placental abruption, velamentous cord insertion - maternal HTN - anemia - preeclampsia - eclampsia - pyelonephritis

Question 52

what is preeclampsia?

Answer 52

maternal hypertension, proteinuria, and edema after 20th week

Question 53

what is another name of eclampsia?

Answer 53

toxemia of pregnancy

Question 54

what is IUGR?

Answer 54

intrauterine growth restriction - discordant growth between the 2 twins

Question 55

weight difference of twins with IUGR?

Answer 55

15-20% 500+ gram difference at birth

Question 56

what measurement is best to assess for IUGR?

Answer 56

abdominal circumference (>20mm)

Question 57

what is TTTS?

Answer 57

twin to twin transfusion syndrome abnormal arteriovenous circulation in the placenta with abnormal shunting of blood from one fetus to another

Question 58

in TTTS the ____ system of donor pumps blood to ____ system of recipient

Answer 58

arterial system; venous system

Question 59

other names for donor twin?

Answer 59

pump twin; stuck twin

Question 60

what type of placenta can TTTS occur in?

Answer 60

monochorionic only

Question 61

in TTTS, what are characteristics of the pump twin?

Answer 61

smaller, oligohydramnios, IUGR, anemic

Question 62

in TTTS, what are characteristics of the recipient twin?

Answer 62

bigger, polyhydramnios, too much blood, possible CHF

Question 63

what does TRAP stand for?

Answer 63

twin reversed arterial perfusion

Question 64

other names for TRAP?

Answer 64

acardiac/acephalic twin

Question 65

TRAP is a form of TTTS. T/F?

Answer 65

true

Question 66

what type of placentation is most common with TRAP?

Answer 66

monochorionic monoamniotic

Question 67

what is interlocking twin syndrome?

Answer 67

a mo-mo pregnancy where one twin is breeched and the other is cephalic

Question 68

selective termination can only occur with ____ pregnancies

Answer 68

dichorionic

Question 69

most common method for selective termination?

Answer 69

injection of potassium chloride into fetus' heart