Multiple Multiple PregnancyPregnancy

Max Brinsmead MB BS PhDMax Brinsmead MB BS PhDMay 2015May 2015

Incidence of Multiple Incidence of Multiple PregnancyPregnancy

Twins 1:80 in CaucasiansTwins 1:80 in Caucasians Assisted conception (IVF) explains most Assisted conception (IVF) explains most

of the increasing incidenceof the increasing incidence But incidence is also affected by:But incidence is also affected by:

Race (1:50 Black Africans, 1:150 in Asians)Race (1:50 Black Africans, 1:150 in Asians) Family history (mean FSH levels)Family history (mean FSH levels) Older maternal ageOlder maternal age Increasing parityIncreasing parity

Spontaneous triplets 1:6400 (Hellin’s Spontaneous triplets 1:6400 (Hellin’s Law)Law)

Why are Multiples a Why are Multiples a Problem?Problem? PrematurityPrematurity

Risk of pre term delivery twins increased 5-foldRisk of pre term delivery twins increased 5-fold And 10-fold for tripletsAnd 10-fold for triplets 14% twins and 41% triplets born very pre-term14% twins and 41% triplets born very pre-term

Intrauterine growth restrictionIntrauterine growth restriction Often manifest as discordant growthOften manifest as discordant growth

Congenital malformations increased 2-Congenital malformations increased 2-foldfold

In monochorionic twins onlyIn monochorionic twins only

Increased rate of maternal pregnancy Increased rate of maternal pregnancy disordersdisorders

e.g. Pre eclampsia, gest. Diabetes, APH etce.g. Pre eclampsia, gest. Diabetes, APH etc

Overall PN mortality increased 2 – 3-foldOverall PN mortality increased 2 – 3-fold

IS CHORIONICITYIS CHORIONICITY

But the single most important But the single most important predictor of Risk in a twin predictor of Risk in a twin

pregnancypregnancy

Types of twin pregnancyTypes of twin pregnancy Dizygotic – arise from two eggs.Dizygotic – arise from two eggs.

These are non-identical twinsThese are non-identical twins Monozygotic – one egg or embryo that splitsMonozygotic – one egg or embryo that splits

These are identical twins (clones)These are identical twins (clones) But from a clinical perspective it is chorionicity But from a clinical perspective it is chorionicity

that is importantthat is important Dichorionic (two chorion, separate sacs and Dichorionic (two chorion, separate sacs and

placentas)placentas) Monochorionic (one chorion and a shared Monochorionic (one chorion and a shared

placenta)placenta) Monochorionic and diamniotic (separate Monochorionic and diamniotic (separate

sacs)sacs) Monochorionic and monamniotic (only 1%)Monochorionic and monamniotic (only 1%)

About 1/3 twin pregnancies are About 1/3 twin pregnancies are monochorionicmonochorionic

Early Diagnosis is Early Diagnosis is ImportantImportant

The early diagnosis of twins is one of the The early diagnosis of twins is one of the reasons to advocate universal 1reasons to advocate universal 1stst trimester trimester scansscans

There are implications for prenatal screening There are implications for prenatal screening for aneuploidyfor aneuploidy

ANDAND It is the best time to document chorionicityIt is the best time to document chorionicity

By looking for and studying the gestational By looking for and studying the gestational sac(s)sac(s)

““Y” sign = dichorionicY” sign = dichorionic ““T” sign = monochorionicT” sign = monochorionic

If in doubt refer for specialist scanning before If in doubt refer for specialist scanning before 14 weeks14 weeks

Monochorionic Twin Monochorionic Twin ProblemsProblems

Almost all monochorionic twins share Almost all monochorionic twins share vessels in their common placentavessels in their common placenta

But for 10 – 15% unidirectional flow results But for 10 – 15% unidirectional flow results in twin-to-twin transfusion (TTS) which can:in twin-to-twin transfusion (TTS) which can:

Cause discordant growthCause discordant growth Has cardiovascular , haematological and amniotic Has cardiovascular , haematological and amniotic

fluid burdensfluid burdens Result in the death of one twinResult in the death of one twin And a high risk of neurological damage to the And a high risk of neurological damage to the

survivorsurvivor

MC and MA twinsMC and MA twins Are at high risk of cord entanglementAre at high risk of cord entanglement Or succumb to acute polyhydramnios in the 2Or succumb to acute polyhydramnios in the 2ndnd

trimestertrimester

Management of Twin Management of Twin PregnancyPregnancy Patient counsellingPatient counselling

Issues of prenatal diagnosisIssues of prenatal diagnosis Nutrition and restNutrition and rest More frequent AN visitsMore frequent AN visits Dealing with the discomforts of Dealing with the discomforts of

pregnancypregnancy Place of deliveryPlace of delivery Timing of deliveryTiming of delivery Mode of deliveryMode of delivery Rearing twinsRearing twins A role for Support GroupsA role for Support Groups

Management of Twin Management of Twin PregnancyPregnancy

Scan MC twins every 2 – 3 weekly from Scan MC twins every 2 – 3 weekly from 16w16w

Best outcomes from TTS occur if it is diagnosed <24 Best outcomes from TTS occur if it is diagnosed <24 wkswks

Refer to a Perinatal CentreRefer to a Perinatal Centre IUFD of one twin also requires Perinatal Centre IUFD of one twin also requires Perinatal Centre

reviewreview Scan MC twins at 22w for cardiac defectsScan MC twins at 22w for cardiac defects

Scan DC twins at 28, 34 and 36wScan DC twins at 28, 34 and 36w or as clinically indicatedor as clinically indicated Add Doppler flow studies of umbilical arteryAdd Doppler flow studies of umbilical artery

Cervical length monitoring?Cervical length monitoring? Low threshold for admissionLow threshold for admission

But routine “bed rest” long abandonedBut routine “bed rest” long abandoned

When to Deliver?When to Deliver?

NICE Recommendations:NICE Recommendations: 35 completed weeks for monochorionic twins35 completed weeks for monochorionic twins 37 completed weeks for dichorionic twins37 completed weeks for dichorionic twins

The ANZ RCT of elective IOL at 37 weeks vs The ANZ RCT of elective IOL at 37 weeks vs standard carestandard care 235 women in multiple centres235 women in multiple centres Stopped early through lack of fundingStopped early through lack of funding Fewer SGA infants from IOL (RR = 0.39, CI 0.20 – 0.750 Fewer SGA infants from IOL (RR = 0.39, CI 0.20 – 0.750

and a trend towards fewer adverse infant outcomes and a trend towards fewer adverse infant outcomes (death, serious trauma, seizures, NICU admission >4 (death, serious trauma, seizures, NICU admission >4 days etc)days etc)

Because of the very poor prognosis associated Because of the very poor prognosis associated with MCMA pregnancies many perinatologists with MCMA pregnancies many perinatologists recommend:recommend: El CS at 32w after steroidsEl CS at 32w after steroids

Management of Twin Management of Twin LabourLabour

Elective CS for a leading twin breechElective CS for a leading twin breech A role for epidural anaesthesia (but not A role for epidural anaesthesia (but not

mandatory)mandatory) IV line. Group and saveIV line. Group and save Continuous monitoring if there is any other Continuous monitoring if there is any other

complication e.g. premature or discordantcomplication e.g. premature or discordant Second twin requires presence of an obstetrician Second twin requires presence of an obstetrician

& someone capable of neonatal resuscitation& someone capable of neonatal resuscitation Take steps to deliver 2Take steps to deliver 2ndnd twin within 20 – 40 min twin within 20 – 40 min PPH prophylaxisPPH prophylaxis Consider thromboprophylaxisConsider thromboprophylaxis

Any Questions or Any Questions or Comments?Comments?

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