Zygosity Flashcards
what type of monozygotic twins has the highest morality?
monochorionic/monoamniotic monozygotic twins
what are the 3 different zygosities of monozygotic twins?
monochorionic/monoamniotic
monochorionic/diamniotic
dichorionic/diamniotic
at what time after fertilisation does cleavage occur resulting in different plantations of monozygotic twins?
monochorionic/monoamniotic = days 8-12
monochorionic/diamniotic = days 4-8
dichorionic/diamniotic = first 3 days
> day 12 = conjoined twins
what happens if cleavage of a fertilised ova occurs after day 12?
conjoined twins
what are some of the complications with multiple pregnancies?
high perinatal morbidity and mortality abortion (vanishing twin) nausea and vomiting pre term labour polyhydramnios congenital anomalies placenta abruption placenta praevia discordant twin growth malpresentation cord prolapse post partum haemorrhage
what are some of the causes of perinatal morbidity and mortality with multiple pregnancies?
prematurity (RDS) birth trauma cerebral haemorrhage birth asphyxia congenital anomaly still birth
what is twin-twin transfusion?
one feotus donates their blood to the other foetus due to an anastomoses of blood vessels
the recipient gets heart failure, polyhydramnios and hydros
what are the consequences of the donor in twin-twin transfusion?
oligohydramnios
intrauterine growth restriction
how is twin-twin transfusion corrected?
fetoscopic ablation of mnastomoses
amnio-reduction of foetal recipient
selective foetal reduction
intrauterine blood transfusion for donor
how is the foetal preterm labour risk associated with multiple pregnancies reduced?
steroids for foetal lung maturation
serial cervical length assessment
what sign on USS is suggestive of diamniotic/monochorionic monozygotic twins?
T sign
what sign on USS is suggestive of diamniotic/dichorionic monozygotic twins?
lambda sign
