Multiple Pregnancy and Preterm Birth Flashcards
Describe the difference between zygosity and chorionicity.
- Zygosity
- Number of embryos
- Chorionicity
- Number of placentas
What are some complications of monochorionicity?
- Severe IUGR
- Conjoined twins
- Higher perinatal mortality
- Higher NICU admissions
- Twin-twin transfusion syndrome
Using ultrasound, how is gestational age determined in a multiple pregnancy?
Using the larger twin (in case of some undetected growth pathology in the other)
List some maternal complications of multiple pregnancies
- Pre-eclampsia - aspirin (100mg/day) recommended 12-36 weeks. Assists placental implantation
- Gestational diabetes - more likely, formal OGTT recommended
- Antepartum/postpartum haemorrhage - 3 and 4-fold more likely
- Anaemia - 3-fold risk
- Depression (ante/postnatal) - 5-fold increase in post-natal depression (and severity, duration increase)
- Marital disharmony - 50% end within 2 years of triplets
List some foetal complications of multiple pregnancies
- Higher foetal anomaly rate in monozygotic twins
- Lower birth weight
- TTTS
- Growth velocity decreases earlier
- Increased perinatal mortality
Describe how chorionicity and amnionicity affect the timing of birth compared to singleton pregnancies
- DC DA twins - 37 to 37+6
- MC DA twins - 36 to 37+6
- MC MA twins - 32 to 33+6
What is the underlying pathology in twin-twin transfusion syndrome?
- Unbalanced intertwin transfusion through AA and VV anastomoses in a shared placenta (monochorionic twins), or AV anastomoses where the vessels pierce the chorionic plate
What are the complications to donor and recipient twins in twin-twin transfusion syndrome?
How is it detected?
- Donor twin: anaemia, oliguria, hypovolaemia, oligohydramnios, IUGR, FDIU
- Recipient twin: polycythaemia, polyuria, hypervolaemia, polyhydramnios, cardiomyopathy, FDIU
- Detection: twin oligo/polyhydramnios sequence, MCA velocity/polycythaemia
How is twin-twin transfusion syndrome treated?
- Amniodrainage and septostomy - 60-70% survival, 30% long-term neuro sequelae
- Selective laser photocoagulation of placental vessels - 75-90% survival, 10% long-term neuro sequelae
Define what is meant by low birthweight
- Low < 2500g
- Very low < 1500g
- Extremely low < 1000g
Define what is meant by preterm birth
- Preterm < 37 weeks
- Very preterm < 32 weeks
- Extremely preterm < 28 weeks
What is meant by “small for dates” or “small for gestational age”
- < 10th centile on appropriate chart OR < 2SD
Describe some causes of low birthweight
- Normal
- Maternal
- Environmental, PE/hypertensive/renal disorders
- Foetal
- Infections, chromosomal abnormalities, major malformations
- Placental
- Multiple pregnancies, poor implantation, malformations, placental insufficiency
What are some causes of preterm birth?
- Preterm labour/PROM
- Cervical incompetence
- Multiple pregnancies
- APH
- Uterine abnormalities
- Indicated delivery (foetal or maternal)
What are some problems that affect preterm babies?
- Mortality
- Respiratory distress
- Hypothermia/glycaemia
- Feeding issues
- Jaundice
- Fluid balance/Na/Ca/Mg imbalance
- Apnoea
- Intraventricular haemorrhage
- Cardiac/gut issues
- Anaemia
- Adverse long term outcomes (Barker hypothesis)
