Lec13 - Multiple pregnancies Flashcards
Twin pregnancy incidence per 1000 births in Europe?
9-20
Twin pregnancy incidence per 1000 births in Far East?
2-7
Twin pregnancy incidence per 1000 births in Nigeria?
20-45
What does the geographical variation in twin incidence suggest?
Supports the idea that there is a genetic component of having twins
What other evidence supports the genetic component of twins?
Superovulation/FH of twins
Why/ where might having twins be an advantage?
In areas where perinatal and neonatal/infant loss rates are high
Why has the incidence of twins increased over time?
Due to maternal age (women having babies later) and IVF availability
Why might the incidence of triplets and higher order births potentially be reducing following a peak in 1998?
Greater awareness that higher order births are more risky
What are the aetiological factors for super ovulation?
Ethnicity Family history Increasing maternal age Increasing parity Fertility treatment
What are the three ways of describing the type of pregnancy?
Zygosity
Chorionicity
Amnionicity
What does monozygous mean?
The twins come from the same egg and are identical
What does dizygous mean?
The twins come from two eggs and are non-identical
What tissue does the amniotic sac develop from?
Ectoderm
When does embryonic folding occur?
In week 4
What tissue does the chorion originate from?
Mesoderm
