Transcript A Multifocal Audit of Obstetric Practice in a Provincial

Multiple Pregnancy
Max Brinsmead MB BS PhD
May 2015
Incidence of Multiple Pregnancy
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Twins 1:80 in Caucasians
Assisted conception (IVF) explains most of the
increasing incidence
But incidence is also affected by:
Race (1:50 Black Africans, 1:150 in Asians)
 Family history (mean FSH levels)
 Older maternal age
 Increasing parity
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Spontaneous triplets 1:6400 (Hellin’s Law)
Why are Multiples a Problem?
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Prematurity
Risk of pre term delivery twins increased 5-fold
 And 10-fold for triplets
 14% twins and 41% triplets born very pre-term
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Intrauterine growth restriction
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Congenital malformations increased 2-fold
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In monochorionic twins only
Increased rate of maternal pregnancy disorders
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Often manifest as discordant growth
e.g. Pre eclampsia, gest. Diabetes, APH etc
Overall PN mortality increased 2 – 3-fold
But the single most important
predictor of Risk in a twin
pregnancy
IS CHORIONICITY
Types of twin pregnancy
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Dizygotic – arise from two eggs.
 These are non-identical twins
Monozygotic – one egg or embryo that splits
 These are identical twins (clones)
But from a clinical perspective it is chorionicity that is
important
 Dichorionic (two chorion, separate sacs and
placentas)
 Monochorionic (one chorion and a shared placenta)
 Monochorionic and diamniotic (separate sacs)
 Monochorionic and monamniotic (only 1%)
About 1/3 twin pregnancies are monochorionic
Early Diagnosis is Important
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The early diagnosis of twins is one of the reasons to
advocate universal 1st trimester scans
There are implications for prenatal screening for
aneuploidy
AND
It is the best time to document chorionicity
 By looking for and studying the gestational sac(s)
 “Y” sign = dichorionic
 “T” sign = monochorionic
If in doubt refer for specialist scanning before 14 weeks
Monochorionic Twin Problems
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Almost all monochorionic twins share vessels in
their common placenta
But for 10 – 15% unidirectional flow results in
twin-to-twin transfusion (TTS) which can:
Cause discordant growth
 Has cardiovascular , haematological and amniotic fluid
burdens
 Result in the death of one twin
 And a high risk of neurological damage to the survivor
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MC and MA twins
Are at high risk of cord entanglement
 Or succumb to acute polyhydramnios in the 2nd trimester
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Management of Twin Pregnancy
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Patient counselling
Issues of prenatal diagnosis
Nutrition and rest
More frequent AN visits
Dealing with the discomforts of pregnancy
Place of delivery
Timing of delivery
Mode of delivery
Rearing twins
A role for Support Groups
Management of Twin Pregnancy
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Scan MC twins every 2 – 3 weekly from 16w
Best outcomes from TTS occur if it is diagnosed <24 wks
 Refer to a Perinatal Centre
 IUFD of one twin also requires Perinatal Centre review
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Scan MC twins at 22w for cardiac defects
Scan DC twins at 28, 34 and 36w
or as clinically indicated
 Add Doppler flow studies of umbilical artery
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Cervical length monitoring?
Low threshold for admission
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But routine “bed rest” long abandoned
When to Deliver?
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NICE Recommendations:
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The ANZ RCT of elective IOL at 37 weeks vs standard care
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35 completed weeks for monochorionic twins
37 completed weeks for dichorionic twins
235 women in multiple centres
Stopped early through lack of funding
Fewer SGA infants from IOL (RR = 0.39, CI 0.20 – 0.750 and a trend
towards fewer adverse infant outcomes (death, serious trauma, seizures,
NICU admission >4 days etc)
Because of the very poor prognosis associated with MCMA
pregnancies many perinatologists recommend:
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El CS at 32w after steroids
Management of Twin Labour
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Elective CS for a leading twin breech
A role for epidural anaesthesia (but not mandatory)
IV line. Group and save
Continuous monitoring if there is any other complication
e.g. premature or discordant
Second twin requires presence of an obstetrician & someone
capable of neonatal resuscitation
Take steps to deliver 2nd twin within 20 – 40 min
PPH prophylaxis
Consider thromboprophylaxis
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