Multiple Pregnancies Flashcards
Why do the chances of having a multiple pregnancy increase with an increase in maternal age?
Because older women release more FSH which increases the chances of another egg being released.
What proportion of twins are monozygous and dizygous?
1/3 Monozygous
2/3 Dizygous
What is amnion?
The innermost membrane that encloses the embryo and it contributes to the formation of the placenta.
What is chorion?
The outermost membrane that surrounds the embryo
How can a twin pregnancy be diagnosed?
- Ultrasound
- Uterus larger than expected
What causes a pregnancy to be monochorionic and diamniotic?
Splitting occurs whilst it is a blastocyte (approx. 4 days and inner cell mass forms at this time).
This causes there to be two inner cell masses and there is a common chorion but separate amnions and a joined placenta.
What causes a pregnancy to be monochorionic and monoamniotic?
Splitting occur later so both embryos originate from one inner cell mass.
As a result, there is a common chorion, amnion and placenta.
What are the different types of mortality during and after pregnancy?
- Stillbirth: After 24 weeks
- Early neonatal: First 7 days
- Neonatal: First 28 days
- Perinatal: Stillbirth + Early neonatal
- Infant: Within first year
How does mortality during pregnancy vary with multiple pregnancies?
Risk of mortality increases with twins and further increases with triplets and so on…
What is the management of twin pregnancies in the first trimester?
- Discuss screening for chromosomal abnormalities
- Determine chorionicity
- Discuss foetal reduction if triplets or more
What is foetal reduction?
Reducing the number of foetuses in a multiple pregnancy
What is the management of twin pregnancies in the second trimester?
- Detection of foetal abnormalities
- Serial scans for growth every month after 24 weeks
- Serial scans for TTTS in monochorionic twins (Twin-to-Twin Transfusion Syndrome)
What is Twin-to-Twin Transfusion Syndrome?
A disease of the shared placenta where there is abnormal blood vessels, leading to a lack of blood supply because maternal blood first goes through a ‘donor’ twin before it reaches the ‘recipient’ twin.
When are dichorionic twins born and how?
37-38 weeks and vaginally or caesarian
When are monochorionic twins born and how?
36-37 weeks and by caesarian
