Multiple pregnancy

Question 1

What is Multiple Pregnancy?

Answer 1

birth of more than 1 baby from a single pregnancy

Question 2

What are the types of twin pregnancies?

Answer 2

1. Monozygotic twins
2. Dizygotic twins

Question 3

Monozygotic twins can also be called?

Answer 3

Identical twins
Uniovular twins

Question 4

Dizygotic twins can also be called?

Answer 4

Fraternal twins
Nonidentical twins
Binovular twins

Question 5

What are Monozygotic twins?

Answer 5

refers to 2 embryos developing from 1 fertilized zygote

Question 6

What are Dizygotic twins?

Answer 6

refers to 2 embryos developing from 2 distinct zygotes

Question 7

Dizygotic twins are always classified as?

Answer 7

Dichorionic Diamniotic (DCDA)

Question 8

Monozygotic twins can be classified as?

Answer 8

1. Monochorionic Diamniotic (MCDA)
2. Monochorionic Monoamniotic (MCMA)
3. Dichorionic Diamniotic (DCDA)
4. Conjoint twins

Question 9

What is the most common type of Monozygotic twins?

Answer 9

Monochorionic Diamniotic

Question 10

What is the least common type of Monozygotic twins?

Answer 10

Dichorionic Diamniotic

Question 11

What is Chorionicity?

Answer 11

refers to the # of placenta (think chorionic plate of the placenta)

Question 12

What is Amnionicity?

Answer 12

refers to the # of fetal membranes (think amniotic sac)

Question 13

What is Zygosity?

Answer 13

refers to the # of ova

Question 14

If the zygote splits < 4 days post-fertilization, you get?

Answer 14

Dichorionic Diamniotic twins

Question 15

if the zygote splits between 4-8 days post-fertilization, you get?

Answer 15

Monochorionic Diamniotic twins

Question 16

if the zygote splits between 8-14 days post-fertilization, you get?

Answer 16

Monochorionic Monoamniotic twins

Question 17

if the zygote splits after 14 days, post-fertilization, you get

Answer 17

Conjoint twins

Question 18

Why would Conjoint twins result, when the zygote splits after 14 days post-fertilization?

Answer 18

because: the primitive streak is fully formed after 14 days, so if the zygote splits at this point you would have incomplete splitting of the germinal disc

Question 19

Why would Monochorionic Diamniotic twins result, when the zygote splits between 4 & 8 post-fertilization?

Answer 19

because: the chorion is fully formed between 4 & 8 days, so only 1 placenta would result. However the amniotic cavity is not yet formed, so 2 amniotic sacs would result.

Question 20

Why would Monochorionic Monoamniotic twins result, when zygote splits between 8 & 14 days post-fertilization?

Answer 20

because the chorion and amniotic cavity are already formed between 8 & 14 days, so only 1 placenta and 1 amniotic sac would result.

Question 21

Why would Dichorionic Diamniotic twins result, when the zygote splits before 4 post-fertilization?

Answer 21

because neither the chorion or amniotic sac is formed at the 8 cell stage, so 2 placentas & 2 amniotic sacs would result.