Multiple Pregnancy Flashcards
What is monozygotic? Dizygotic? Monoamniotic? Diamniotic? Monochorionic? Dichorionic?
Monozygotic: identical twins (from a single zygote)
Dizygotic: non-identical (from two different zygotes)
Monoamniotic: single amniotic sac
Diamniotic: two separate amniotic sacs
Monochorionic: share a single placenta
Dichorionic: two separate placentas
The best outcomes are with diamniotic, dichorionic twin pregnancies, as each fetus has their own nutrient supply.
What is monozygotic? Dizygotic? Monoamniotic? Diamniotic? Monochorionic? Dichorionic?
There are some key definitions to become familiar with relating to twin and multiple pregnancy:
Monozygotic: identical twins (from a single zygote)
Dizygotic: non-identical (from two different zygotes)
Monoamniotic: single amniotic sac
Diamniotic: two separate amniotic sacs
Monochorionic: share a single placenta
Dichorionic: two separate placentas
The best outcomes are with diamniotic, dichorionic twin pregnancies, as each fetus has their own nutrient supply.
When is multiple pregnancy usually diagnosed?
What is also done?
Multiple pregnancy is usually diagnosed on the booking ultrasound scan. Ultrasound is also used to determine the:
Gestational age
Number of placentas (chorionicity) and amniotic sacs (amnionicity)
Risk of Down’s syndrome (as part of the combined test)
How is type of twins determined by ultrasound appearance?
When determining the type of twins using an ultrasound scan:
Dichorionic diamniotic twins have a membrane between the twins, with a lambda sign or twin peak sign
Monochorionic diamniotic twins have a membrane between the twins, with a T sign
Monochorionic monoamniotic twins have no membrane separating the twins
Complications of twin pregnancy on mother?
Baby?
Risks to the mother:
Anaemia Polyhydramnios Hypertension Malpresentation Spontaneous preterm birth Instrumental delivery or caesarean Postpartum haemorrhage
Risks to the fetuses and neonates:
Miscarriage Stillbirth Fetal growth restriction Prematurity Twin-twin transfusion syndrome Twin anaemia polycythaemia sequence Congenital abnormalities
What is twin-twin transfusion syndrome?
Treatment?
Twin-twin transfusion syndrome occurs when the fetuses share a placenta. It is called feto-fetal transfusion syndrome in pregnancies with more than two fetuses.
When there is a connection between the blood supplies of the two fetuses, one fetus (the recipient) may receive the majority of the blood from the placenta, while the other fetus (the donor) is starved of blood. The recipient gets the majority of the blood, and can become fluid overloaded, with heart failure and polyhydramnios. The donor has growth restriction, anaemia and oligohydramnios. There will be a discrepancy between the size of the fetuses.
Women with twin-twin transfusion syndrome need to be referred to a tertiary specialist fetal medicine centre. In severe cases, laser treatment may be used to destroy the connection between the two blood supplies.
What is twin anaemia polycythaemia sequence?
Twin anaemia polycythaemia sequence is similar to twin-twin transfusion syndrome, but less acute. One twin becomes anaemic whilst the other develops polycythaemia (raised haemoglobin).
Antenatal care for women with multiple pregnancy?
