Multiple pregnancy Flashcards
Monozygotic vs dizygotic
Mono - identical twins- single zygote
Dizygotic - non identical twins (2 zygotes)
Monoamniotic vs diamniotic
Single shared amniotic sac vs two seperate sacs
Monochorionic vs dichorionic
Single shared vs two seperate placentas
which type of twins have the best outcomes
Diamniotic
Dichorionic
Each foetus has own nutrient supply
When does the embryo seperate for dichorionic diamniotic twins
Before day 3/before implantation
When does an embryo split to be diamnitoic (2 sacs) and monochorionic (1placenta)
Days 4-8 - splits stright after implantation
When does an embyo split for twins to be monoamniotic and monochorionic (shared placenta and sac)
After day 8 - while after implatation
When are twins noticed
Booking US
What is the booking US
Gestational age
Number of placentas (chprionicity) + amniotic sacs (amnionicity)
Risk of Downs syndrome (as part of combined test)
What sign is seen in dichorionic diamniotic twins?
Lambda sign or twin peak sign
Membrane between twins
What sign is shown on US in monochorionic diamnitoic twins?
T sign
Membrane between the twins
What is a lambda sign or twin peak sign?
Triangular appearance where membrane meets chorion (as it partially blends into membrane)
Indicated sepearate placentas
What is the T sign
Membrane between twins abruptly meets chroion, gives T appearance
Indicates monochorionic twin pregnancy (single placenta)
Complications of multiple pregnancy to mother
Anaemia
Polyhydrmainos
HPTN
malpresentation
Spontaneous preterm birth
Insturmental delivery or C section
Postpartum haemorrhage
Multiple pregnancy risk to foetus and noenates
Miscarraige
Stillbirth
Foetal Growth restriction
Prematurity
Twin-twin transfusion sequence
Twin anaemia polycythaemia sequnce
Congenital abnormalities
WHat is twin twin transfusion syndrome
A connection between the blood supply to the foetuses = one oetus is starved of blood, other is overloaded
What can happen to the recipient in twin twin transfusion syndrome
Majortiy of blood received -> fluid overloaded
HF , polyhydraminos
What happends to the donor in twin twin transfusion syndrome
Growth restricition, anaemia and oligohydraminos
What is foeto-foetal transfusion syndrome?
Twin-twin transfusion syndrome in pregnancies with more than two foetuses
Treatment for twin twin tranfusion syndrome
Laser treatment
What is oligohydraminos
Not receiving enough fluid therefore not passing enough
Why is the recepient twin polycythaemic in TTTS?
Becomes hypoxic because donor twin deoxygenates blood supply - stimulates kidneys to increase erythropoeitin EPO -> stimulation of bone marrow to increase RBC -> polycythaemia
WHy is the recipient hypoxic in TTTS?
Deoxygenated blood from donor is coming to recipient
Why does recipient baby have increased risk of stroke
Polycythaemia - viscosity increased
What is selective reduction
Killing one of the babies so the other survives
How does selective reduction happen
Clamp cord of one
Inject potassium chloride
When is selective reduction best to be done
16 weeks
How do you choose the baby that survives
Cardiac function, brain blood flow etc - doppler blood flow
What is twin anaemia polycythaemia sequence
One twin becomes anaemic whilst the other develops polycythaemia (raised haemoglobin).
Less acute than TTTS
What do women with multiple pregnancy require additional monitoring for?
Anaemia
How do you monitor for anaemia in multiplepregnacy
FBC at booking clinic, 20 weeks gestation, 28 weeks gestation
why are additional US scans are required in multiple pregnancy
to monitor for foetal growth restriction, unequal growth and twin twin transfusion syndrome
What additional scans are done in multiple pregnancies - mono vs dichroionic
Monochorionic - 2 weekly scans from 16 weeks
Dichorionic - 4 weekly scans from 20 weeks
When is planned birth offered for uncomplicated monochorionic monoamniotic twins
32 and 33+6 weeks
When is planned birth offered for monochorionic diamniotic twins
36 adn 36+6 weeks
When is planned birth offered for uncomplicated dichorionic diamniotic twins
37 and 37+6 weeks
When is planned birth for triplets
35+.6 weeks
Why are corticosteroids given to multiple pregnancies before delivery
Help mature the lungs
Which twins reuqire a C sections
Monoamniotic twins
Between 32 and 32+6 weeks
When is vaginal delivery possible with diamniotic twins?
Cephalic presentation in first baby
C section may be necessary after successful delivery of the first
When is elective C section advised for diamniotic twins
Presenting twin is not cephalic
Whem cam delier second twin vaginally
When out 30 mins after first
Uterus contracts after first twin born and can cut off supply to second baby
