Multiple pregnancies Flashcards
What is the incidence of multiple pregnancy?
2-7% in far east, 9-20% Europe, 2-45% Nigeria
- Geographic variation suggests genetic component. Superovulation/FH of twins as extra evidence
- At an advantage if perinatal and infant loss rates high
- Incidence of multiple births may be due to age and IVF
Suggest 5 factors that may be implicated in ‘superovulation’
- Ethnicity
- Increased maternal age
- Increased parity
- Family history
- Fertility treatment
There are 2 factors important to consider in multiple pregnancy.
ZYGOSITY
Define it.
Zygosity describes the level of similarity between the alleles in an organism.
There are 2 factors important to consider in multiple pregnancy.
ZYGOSITY
Discuss Dizygous twins
Dizygous- 2 eggs fertilised= non identical twins
- 2/3 of twins
- Seperate amnions, chorions and placentae
- DCDA (Dichorionic diamniotic twin pregnancy)
There are 2 factors important to consider in multiple pregnancy.
ZYGOSITY
Discuss Monozygous twins
Monozygous - 1 egg fertilised = identical twins
- Splitting very early in blastocyst yields 2 inner cell masses (24 hours post fertilisation)
- Share a common chorion, seperate amnions and “joined” placentae
- MCDA (monochorionic diamniotic) - Late splitting yields two embryos from one inner cell mass
- Share chorion, amnion and “joined” placentae
- MCMA (monochorionic, monoamniotic)
There are 2 factors important to consider in multiple pregnancy.
CHORIONICITY
Define it.
Number or placentas/sac
There are 2 factors important to consider in multiple pregnancy.
CHORIONICITY
How does it vary between monozygous and dizygous twins
- All dizygous twins are dichorionic (they have seperate circulations). Dichorionic twins must by diamniotic.
- Monozygous twins may be monochorionic (2/3) or dichorionic (1/3)
- MC have vascularly joined placenta
- MC twins 3x increased loss rate
- MC twins usually diamniotic
How do you diagnose multiple pregnancies?
- Uterine size
- Ultrasound
** Up to 50% discovered at birth worldwide
State 5 possible complications of multiple pregnancies
- “Everything except post-dates”- complications more common
- Symptoms of pregnancy
- Anaemia
- Hypertension
- Intrauterine growth restriction
- Pre-term labour
- Delivery problems perinatal mortality
How does the rate of stillbirths, perinatal, neonatal and infant death vary with multiple pregnancy
Increase as number of embryos increase
How do you manage multiple pregnancies?
- During the first trimester discuss screening for chromosomal anomalies , determine chorionicity and discuss fetal reduction if triplets or more
- During second trimester detect any fetal abnormalities, serial scans for growth for all. Serial scanns for TTTS if MC twins, monthly from 24 weeks if DC
- During third trimester repeat 2nd trimester scanning, monitor BP, be cautious or pre-term labour, delivery planning
Any maternal complications?
Why might you exercise more caution when dealing with monochorionic twin pregnancy?
More fetal malformation, more fetal growith restriction and twin-twin fusion
- unbalanced placental vascular anastomoses
- donor smaller, decreased liquor
- high mortality
- Rx- laser or amnio-reduction
- early delivery by c-section
- unidirectional AV- shunt in twin-twin transfusion
How does delivery planning differ between DC and MC twins?
DC twins at 37-38 weeks by vaginal birth or c-section
MC twins at 36-37 weeks by c-section
Discuss labour management in the case of twins
What is puerperium and what are effects?
- Monitor both twins, any problems delivering twin 2?
- Risk of postpartum bleed
Puerperium: the 6 weeks post-partum when the mothers reproductive organs are returning to their non-pregnant state
- feeding difficulties
- require social and emotional support
What are the risks of higher order multiples? How would you adjust management?
Rx
- Difficuly peurperium and after
- Postpartum haemorrhage
- Preterm labour
Determine chorionicity, consider fetal reduction and deliver preterm by caesarean
