Twin Pregnancy Flashcards
Natural rate of twinning
1:90
Incidence of dizygotic twins increases with….
Age Parity Weight Height Higher in some families
Multiple pregnancies is suspected in…
Large for date uterine size Multiple foetal HRs detected Multiple foetal parts felt HCG and maternal serum alpha-fetoprotein is elevated for gestational age Pregnancy with ART ]
If multiple pregnancy is suspected, how is this confirmed?
USS
What does ART mean?
Assisted reproduction technique
Two types of twin zygosity
Monozygotic
Dizygotic
What % of twins are dizygotic?
70-80%
How do you get dizygotic twins?
Fertilisation of two ova
What % of twins are monozygotic?
20-30%
How do you get monozygotic twins?
Result from cleavage of a single fertilised ova
In monozygotic twins, what determines placentation?
The timing of cleavage
In dichorionic/diamniotic monozygotic twins, when did cleavage occur?
In the first 3 days after fertilisation
What type of monozygotic twins has the lowest mortality rate of all the monozygotic twins?
Dichorionic/diamniotic
What surrounds dichorionic/diamniotic monozygotic twins?
Each foetus will be surrounded by an amnion and chorion like dizygotic twins
In monochorionic/diamniotic monozygotic twins, when did cleavage occur?
Between day 4 and 8 after fertilisation
Mortality of monochorionic/diamniotic monozygotic twins
25%