Multiple pregnancies Flashcards
Define Dizygotic
Two different oocytes fertilised by two different sperm
Embryo can be different sex and are NOT identical
Define Monozygotic
when one sperm fertilise one egg and the embryo decides into 2
Can share the same placenta and amnion depending on time of separation
Define monochorionic
When twins share the same placenta
Define Dichorionic
When twins have 2 separate placentas
Define Monoamniotic
When twins share the same amniotic membrane
Define Diamniotic
When twins have 2 separate amniotic membranes
Describe dizygotic twins in terms of amniotic and chorionic composition
Diamniotic Dichorionic - DCDA
When does the embryo split to produce Dichorionic Diamniotic twins
Before Day 3 - before implantation
When does the embryo split to produce Monochorionic Diamniotic
Between days 4-8 - after implantation
When does the embryo split to produce Monochorionic Monoamniotic
Between days 9-13 - after implantation
What happens when there is incomplete division of an embryo?
Conjoined twins
List 4 symptoms associated with multiple pregnancy
- Hyperemesis gravidum
- Uterus large for dates
- 3+ foetal poles palpable >24 weeks
- Multiple foetal hearts heard on auscultation
How are multiple pregnancies diagnosed?
US scan during the first trimester (GS)
How is Dichorionicity diagnosed on US? Which sign do we see?
- Two separate placentas seen
- Lamda sign seen <14 weeks
- Different sex babies
What maternal complications are associated with multiple pregnancies? (6)
- Pre-eclampsia (5x)
- Gestational diabetes
- PPH/APH
- Anaemia
- operative delivery
- Placenta privea
Which type of twins has a higher foetal risk?
Monochorionic twins
What are the foetal complications associated with multiple pregnancies?
- Miscarriage
- Congenital abnormalities
- IUGR
- Pre-term labour - increased risk of death
- increased risk of death - intranatally and postnatally
- Disability
What problems can you get with MC twins?
- Twin to twin transfusion syndrome
- Twin reversed arterial perfusion (TRAP)
- IUGR
What is Twin to twin transfusion syndrome?
Occurs due to vascular anastomosis in the shared placenta where one twin takes up all the blood supply (recipient) from the other twin (Donor twin)
What happens to the Donor twin in TTTS
Fluid depleted
IUGR
oligohydraminous
What happens to the Recipient twin in TTTS
Fluid overload
Polycythemia
Cardia faliure
Death
What treatment options are there for TTTS?
- Laser ablation of the placental anastomosis - lowest risk of handicap
- selective foeticide by cord occlusion
What is twin reversed arterial perfusion?
One twin is genetically abnormal (No/non functioning heart) therefore receives blood from the other twin and the umbilical artery blood supply is reversed.
Pumper twin has a high risk of developing cardiac failure
What is the risk on a twin if the other one dies in a dichorionic pregnancy?
In the first trimester: No effect
In the second/third: precipitates labour
What is the risk on a twin if the other one dies in a Monochorionic pregnancy?
Subsequent death or neurological damage due to hypovolemia occurs (shared circulation)
What are the intrapartum risks associated with multiple pregnancies? (5)
- Malpresentation
- Foetal hypoxia in second twin after first one is delivered
- Cord prolapse
- Operative delivery
- PPH
What do you need to do in the antepartum period in any twin pregnancy?
- Consultant led care
- Iron, folic acid and aspirin
- Early US to determine type
At what weeks do you need to do serial scans for twins?
28, 32 and 36
When is it recommended to deliver DCDA twins?
37 weeks
When is it recommended to deliver MC twins?
36 weeks
When is CS indicated?
- Breech or transverse lie
2. All monochorionic twins
How are twins vaginally delivered?
- In theatre usually to allow speedy surgical intervention
- First twin delivered normally
- EXTRA CTG monitoring for second twin.
- Recommended to monitor first twin VIA head and second twin via abdomen
- SCAN/feel for the presentation of the second twin after the first one is delivered
- Consider CS/breech extraction if second baby is in a weird position
- Give oxytocin if the contractions are reduced after the delivery of the first twin
Is TVS measurement of cervical length advised in preterm labour of twins?
NO
Can progesterone prevent preterm twin labour?
NO
What are the complications of laster ablation/coagulation in TTTS? (4)
- Rupture of membranes
- Infection
- Pre-term delivery
- Miscarriage
When is selective reduction advised for multiple pregnancies?
12 weeks
How do we terminate DC twins?
KCL injection before 14 weeks of gestation
How do we terminate MC twins?
Umbilical cord occlusion using diathermy
What increases the risk of having multiple pregnancies? (4)
- Assisted conception
- Genetics
- Increased maternal age
- IVF
