Multiple Gestation Flashcards
What is multiple gestation?
Multiple gestation = pregnancy of more than 1 foetus
What is amnioncity?
Amnionicity = number of amnions (inner membranes) that surrounds foetus in a multiple pregnancy:
- Pregnancies with 1 amnion (all babies share amniotic sac) are monoamniotic
- Pregnancies with 2 amnions are diamniotic
What is chorionicity?
Chorionicity = number of chorionic (outer) membranes that surrounds foetus in a multiple pregnancy:
- If there is 1 membrane, monochorionic
- If there are 2 membranes, dichorionic
What are the different types of twin pregnancies?
What does DCDA stand for?
Dichorionic diamniotic twins
What does MCDA stand for?
Monochorionic diamiotic twins
What does MCMA stand for?
Monochorionic monoamniotic twins
What is the aetiology of multiple gestation?
- More than 1 egg released during 1 menstrual cycle
- If zygote divides after fertilisation
- Identical twins
- IVF treatments
- Often transfer more than 1 embryo to the uterus
How is determiniation of zygosity and chorionicity done?
- Determination of zygosity and chorionicity is done by foetal USS
- Lambda sign shows 2 placentas – diagnosing dichorionic diamniotic twins
- T sign shows single placenta – diagnosing monochorionic diamniotic twins
Is a USS, what sign diagnosis dichorionic diamniotic twins and what sign diagnosis monochorionic diamniotic twins?
Lambda sign - dichorinic diamniotic twins (2 placentas)
T sign - monochorionic diamniotic twins (1 placenta)
What are possible complications of multiple gestation?
- Maternal
- Preterm labour
- Hyperemesis
- Anaemia in pregnancy
- Hypertension
- Gestational diabetes
- Postpartum haemorrhage
- Foetal
- Growth restriction
- Prematurity
- Increased birth complications
- Increased perinatal mortality/morbidity
- In monochorionic twins, higher chance of
- Twin-twin transfusion syndrome – blood moves from one foetus to other due to shared placenta, causing one baby to lose blood
- Selective growth restriction
- Twin anaemia polycythaemia sequence
- Twin reversed arterial perfusion (TRAP)
- Single twin death
Describe the management of multiple gestation?
- Routine care including trisomy 21 screening and structural scans
- Specialist clinic with regular scans to monitor growth and identify complications
- Dichorionic diamniotic required at least 8 antenatal visits
- Monochorionic required at least 11 antenatal visits
- Monitor BP/commence oral iron if required
- Aim for delivery at
- Dichorionic diamniotic (DCDA) – 37 weeks
- Monochorionic diamniotic (MDCA) – 36 weeks
- Triplets – 35 weeks
- Aim for earlier delivery if maternal or foetal complications
- All delivery vaginal, unless first twin isn’t cephalic position and if triplets offer caesarean section
How many antenatal visits are required for dichorionic diamniotic twins, and how many for monochorionic diamniotic twins?
- Dichorionic diamniotic required at least 8 antenatal visits
- Monochorionic required at least 11 antenatal visits
At what weeks should deliver be aimed for: dichorionic diamniotic twins, monochorionic diamniotic twins and triplets?
- Dichorionic diamniotic (DCDA) – 37 weeks
- Monochorionic diamniotic (MDCA) – 36 weeks
- Triplets – 35 weeks
- Aim for earlier delivery if maternal or foetal complications
- All delivery vaginal, unless first twin isn’t cephalic position and if triplets offer caesarean section