Multiple pregnancy for Multiple pregnancy for MRCOGMRCOG

Multiple birth UK 1995Multiple birth UK 1995

No. (Rate/1000 mats) No. (Rate/1000 mats) Ratio Ratio

TwinsTwins 9889 (13.6)9889 (13.6) 1 in 73 1 in 73

TripletsTriplets 318 (0.4)318 (0.4) 1 in 2282 1 in 2282

QuadsQuads 10 (0.0001)10 (0.0001) 1 in 72563 1 in 72563

TotalTotal 10217 (14)10217 (14) 1 in 71 1 in 71

Importance of chorionicity?Importance of chorionicity?

Chorionicity affects pregnancy risk:Chorionicity affects pregnancy risk: Fetal loss ratesFetal loss rates Cerebral palsy ratesCerebral palsy rates

Pregnancy risk assessmentPregnancy risk assessment Twin-twin transfusion syndromeTwin-twin transfusion syndrome Prenatal diagnosisPrenatal diagnosis

Chromosome abnormalityChromosome abnormalityStrucural abnormalityStrucural abnormality

Further schedule of surveillance based on Further schedule of surveillance based on chorionicity (?=delivery mode)chorionicity (?=delivery mode)

Prevalence death & cerebral palsy Prevalence death & cerebral palsy Western Australia 1980-1989Western Australia 1980-1989

15.6

70.5

92.8

1.67.4 26.7

0102030405060708090

100

per 1000 births

Deaths Cerebral palsy

Singleton

Twins

Triplets

Fetal and Perinatal MortalityFetal and Perinatal Mortality

15

12

9

6

3

0

12.1%

1.8%

15

12

9

6

3

0 2.8% 1.6%

MonochorionicDichorionic

Fetal Loss (<24 weeks)

Perinatal Loss (>24 weeks)

Sebire N et al. BrJOG 1997

Presumed zygosity & cerebral palsy Presumed zygosity & cerebral palsy ((Western Austailia 1956-1985)Western Austailia 1956-1985)

ConcordantConcordant DiscordantDiscordant

MonozygoticMonozygotic 66 99

DizygoticDizygotic 00 2121

P=0.0026

Chorionicity versus zygocityChorionicity versus zygocity

0-4 days

4-7 days

7-14 days

Fused or unfused

Dichorionic10%of all tw ins

33% of m onozygous

Diam niotic17% of all tw ins

56% of m onozygous

Conjoined tw ins0.15% of a ll tw ins0.5%m onozygous

M onoam niotic3% of all tw ins

10% of m onozygous

M onochorionic20%of all tw ins

67% of m onozygous

M onozygous30%of all tw ins(All like sexed)

All dichorionic70%of all tw ins

100% of dizygous

Dizygous70% of all tw ins(1/2 like sexed)

All tw ins

Early ultrasound appearancesEarly ultrasound appearances

Scans before 11 weeks Scans before 11 weeks common in AC pregnanciescommon in AC pregnancies

Chorionicity:Chorionicity: 2 clear sacs dichorionic2 clear sacs dichorionic ?1sac monochorionic?1sac monochorionic

Amnionicity:Amnionicity: UncertainUncertain Yolk sac numberYolk sac number

Dichorionic twins (7 weeks)Dichorionic twins (7 weeks)

Ultrasound diagnosis of chorionicityUltrasound diagnosis of chorionicity

“ “T” signT” signMONOCHORIONICMONOCHORIONIC

““Lambda” signLambda” signDICHORIONICDICHORIONIC

Twin-twin transfusion syndromeTwin-twin transfusion syndrome

25% MC twins will have 25% MC twins will have evidence of TTS at 15-17 evidence of TTS at 15-17 weeksweeks

50% 50% severe TTS severe TTS

Severe TTS 80-90% Severe TTS 80-90% mortalitymortality

Death will occur in both Death will occur in both babiesbabies

RecipientRecipient DonorDonor

Indicators of risk of TTTSIndicators of risk of TTTS

11-13 week scan11-13 week scan Discrepancy in CRLDiscrepancy in CRL Discrepancy in NTDiscrepancy in NT

Donor small NTDonor small NT

Receipient raised NTReceipient raised NT

16 week scan16 week scan Infolding of the Infolding of the

membranesmembranes Size discrepancySize discrepancy

Diagnosis of chronic TTTSDiagnosis of chronic TTTS

MonochorionicStuck twinPolyhydramniosGrowth discrepancyDopplerHydropsPROGRESSIVE*

Serial Amniodrainage

Multicentre Registry (Mari et al. 1998)

• 579 cases

• Survival 68%

• Abnormal neonatal head sonograms - 25%

• Normalise amniotic fluid volume• Improves uterine blood flow• Prevents premature labour

Fetoscopic Laser Ablation

Ville et al. 1998 BrJOGDiLia 1998 (TTTS website)

Non-selective

Laser Ablation

202 cases

59% Survival

4% neurological

handicap rate

FLA vs AmniodrainageFLA vs Amniodrainage

n=116, 17-25 weeks’ gestationn=43: Amniodrainage, Bonn;n=73: Laser ablation, Hamburg

Hecher K et al. 1999 AmJOG

Overall survival (NS)

61% 51%

FLA

Abnormal brain scan (p <0.03)

6% 18%

FLA

FLAAmnion Drainage

Gestation at delivery (p <0.02)

40

30

20

10

0

33.7 30.7

TTS in the 3rd trimester?TTS in the 3rd trimester?

REMEMBERREMEMBER

Chronic type TTSChronic type TTS

Acute “late onset” Acute “late onset” TTSTTS AntenatalAntenatal IntrapartumIntrapartum Delivery of twin 1Delivery of twin 1

Mono-amniotic twinsMono-amniotic twins

High mortality rates (upto 50%)High mortality rates (upto 50%)TTTS/Discordant growth unusualTTTS/Discordant growth unusualMonitor amniotic fluid volumeMonitor amniotic fluid volumeColour-flow doppler for cord entanglementColour-flow doppler for cord entanglementMonitoring of uncertain valueMonitoring of uncertain valueDelivery at 32-34 weeks?Delivery at 32-34 weeks?

Prenatal diagnosis in twinsPrenatal diagnosis in twins

ScreeningScreening Nuchal translucencyNuchal translucency Serum screeningSerum screening

Invasive diagnosisInvasive diagnosis Chorionic villous samplingChorionic villous sampling AmniocentesisAmniocentesis

Screening for aneuploidy in twinsScreening for aneuploidy in twins

Calculation of risksCalculation of risks For each fetusFor each fetus For the pregnancyFor the pregnancy

NT screeningNT screening

Biochemical screeningBiochemical screening

Risks of interventionRisks of intervention Invasive procedureInvasive procedure Selective fetocideSelective fetocide

Single puncture amniocentesisSingle puncture amniocentesis

Sebire et al 1996

Miscarriage risk 1-2%

Selective fetocide 8%+

Sample one sac in MC

Careful documentation

CVS in twinsCVS in twins

Single or double entrySingle or double entry Experienced operatorExperienced operator Careful documentationCareful documentation

Sample 1 placenta in Sample 1 placenta in MC twinsMC twinsMiscarriage risk Miscarriage risk 1-2%1-2%

Risk of selective fetocide Risk of selective fetocide 11-13 weeks 5%11-13 weeks 5%

CVS for “high risk”CVS for “high risk”

Twins and fetal abnormalityTwins and fetal abnormality

DichorionicDichorionic Same risk doubledSame risk doubled

MonochorionicMonochorionic ““Teratogenic” stimulusTeratogenic” stimulus Increased risk midline Increased risk midline

abnormalitiesabnormalities Not always cordantNot always cordant

Specific twin abnormalitiesSpecific twin abnormalities

Conjoined twinsConjoined twins

Acardiac twinningAcardiac twinning

Scanning schedule- normalScanning schedule- normal

MonochorionicMonochorionic12 weeks12 weeks16 weeks16 weeks20 weeks20 weeks24 weeks24 weeks27 weeks27 weeks30 weeks30 weeks33 weeks33 weeksDelivery 36 weeksDelivery 36 weeks

DichorionicDichorionic12 weeks12 weeks20 weeks20 weeks28 weeks28 weeks32 weeks32 weeks36 weeks36 weeksDelivery 38 weeksDelivery 38 weeks

Increased surveillance if evidence of TTTS or growth abnormality

Low birthweightLow birthweight

a Singleton

b Twins

c Triplets

d quads

52% twins (n=5416) <2500g compared 6% singletons (Regan 2001)

Delivery of pre-term twinsDelivery of pre-term twins

37

Elective delivery of twinsElective delivery of twins

0

2

4

6

8

10

12

14

16

28 29 30 31 32 33 34 35 36 37 38 39

Gestation (weeks)

Sti

llbir

th r

isk

pe

r 1

00

0 o

ng

oin

g p

reg

na

nc

ies

Sairam et al 2002

Delivery mode?Delivery mode?

ChorionicityChorionicity MonochorionicMonochorionic MononamnioticMononamniotic

Presentation and lie Presentation and lie Breech twin 1Breech twin 1

Fetal/maternal complicationsFetal/maternal complications Preterm labourPreterm labour Growth restrictionGrowth restriction Previous caesarean sectionPrevious caesarean section Elective deliveryElective delivery

ConsiderConsider

Delivery monochorionic diamniotic?Delivery monochorionic diamniotic?

No evidenceNo evidenceElective LSCSElective LSCS Allows early delivery (36-37 weeks)Allows early delivery (36-37 weeks) Avoids late onset TTTSAvoids late onset TTTS Avoids “circulatory charge” T2 after T1 Avoids “circulatory charge” T2 after T1

delivereddelivered Small number of absolute total of twinsSmall number of absolute total of twins

Vaginal deliveryVaginal delivery No antenatal evidence TTTSNo antenatal evidence TTTS Favorable cervix (multips)Favorable cervix (multips) Limit delivery interval Limit delivery interval Monitor T2 carefullyMonitor T2 carefully

Presentations of twinsPresentations of twins

CephalicCephalic BreechBreech OtherOther

CephalicCephalic 38.638.6 13.113.1 0.60.6

BreechBreech 25.525.5 9.29.2 0.60.6

Other Other 8.08.0 3.93.9 0.5 0.5

FIRST TWIN

SECOND TWIN

Percentage of presentation combinations in labour

Breech twin 1Breech twin 1 Prevalent practice =LSCSPrevalent practice =LSCSACOG recommends LSCSACOG recommends LSCSReasons sitedReasons sited

Interlocking twins (1 in 90)Interlocking twins (1 in 90) Interference with decent of Interference with decent of

breechbreech Term breech study (irrelevant)Term breech study (irrelevant) Lack of experience Lack of experience

Vaginal delivery maybe safe Vaginal delivery maybe safe in selected casesin selected cases

EFW1500-3500EFW1500-3500 US no interlocked headsUS no interlocked heads No IUGRNo IUGR Non-footling breechNon-footling breech

0

500

1000

1500

2000

2500

3000

3500

We

igh

t (g

)

Twin 1Twin 2

Weight difference in twins

Audit data SHH 1998

N=45

Twin 1 is not usually bigger than twin 2

Evidence based medicine & twins?Evidence based medicine & twins?

Observational and non-randomised comparative Observational and non-randomised comparative studiesstudies

Address controversyAddress controversy:: mode of delivery of twin 2mode of delivery of twin 2 time interval between delivery of T1 andT2time interval between delivery of T1 andT2 ECV vs breech extractionECV vs breech extraction Trial of scar in twin pregnancyTrial of scar in twin pregnancy

Problem:Problem: retrospective studiesretrospective studies inappropriate measures of outcomeinappropriate measures of outcome recommendations are often empiricalrecommendations are often empirical

Delivery of growth restricted twinsDelivery of growth restricted twins

30-50% IUGR30-50% IUGR ProgressiveProgressive Beginning 32-34wksBeginning 32-34wks Worse after 36wksWorse after 36wks

Offer IOL at 38wksOffer IOL at 38wks Earlier if severe IUGR Earlier if severe IUGR

Doppler assessmentDoppler assessment

Delivery modeDelivery mode EFWEFW Severe discordance (>20%)Severe discordance (>20%)

Vertex/vertexVertex/vertex

Literature supports Literature supports vaginal deliveryvaginal delivery

5% cases T2 will 5% cases T2 will become non-vertex become non-vertex after delivery T1after delivery T1

Report 81% success Report 81% success

Differences of opinionDifferences of opinion ??Perinatal morbidityPerinatal morbidity

Concerns Concerns Head entrapmentHead entrapment

Overall evidence Overall evidence suggests vaginal suggests vaginal delivery is as safe as delivery is as safe as LSCSLSCS

Vertex/breechVertex/breech

VTX/Non-VTX

>2000g<24 weeks

ECV T2

Successful

>24wks & <2000g

Vaginal T1

*Vaginal breech T2

Vaginal T1&T2

*Vaginal breechT2

Probable vaginal T2

Vaginal T1

ECV T2

Unsuccessful UnsuccessfulSuccessful

LSCSLSCS

Probable vaginal T2

*Suitable for vaginal breech

Recent evidence?Recent evidence?

Retrospective 92-97ScotlandAll twin births >24 weeksExcluding

pre-labour IUD Congenital abnormality

PRETERM (vaginal)1438 twin pairs <36/40

23 deaths T1 23 deaths T2

Pulmonary & anoxia

TERM (vaginal) 2436 twin pairs >36/40

No deaths T1 9 deaths T2

7 deaths due to anoxia5 “mechanical” problems

TERM (elective LSCS)454 twin pairs

No deaths T1 or T2

Conclusion

Planned caesarean birth may prevent perinatal deaths

BUT

Chorionicity unknown

(7 of 9 T2 deaths were concordant for sex ie. may be monochorionic)

Smith et al 2002, BMJ

Twin vaginal birth after LSCSTwin vaginal birth after LSCS

Controversial limited data about safetyControversial limited data about safety

Concern ?Concern ?risk of uterine rupturerisk of uterine rupture Over-distentionOver-distention Intrauterine manipulationsIntrauterine manipulations

No evidence of risk No evidence of risk 3 studies no increased risk3 studies no increased risk Other caused of over-distention noOther caused of over-distention noriskrisk

Trial of labour at maternal requestTrial of labour at maternal request

AnalgesiaAnalgesia

Appropriate analgesia essentialAppropriate analgesia essential

Operative delivery may be Operative delivery may be requiredrequired

Increased risk of GAIncreased risk of GA Prophylactic antacidsProphylactic antacids

Anaesthetist available on LWAnaesthetist available on LW

Epidural optimizes vaginal Epidural optimizes vaginal delivery (recommended)delivery (recommended)

Epidural not mandatoryEpidural not mandatory Nitrous oxideNitrous oxide OpiatesOpiates

Issues in monitoring twinsIssues in monitoring twins

““High risk”High risk” EFM EFM

Continuous & simultaneousContinuous & simultaneous

External transducer External transducer T2T2

FSE FSE T1 T1 after ROMafter ROM

Ensure 2 heartbeats seenEnsure 2 heartbeats seen

Careful monitoring after Careful monitoring after delivery of T1 delivery of T1 (ultrasound aids (ultrasound aids transducer positioning)transducer positioning)

‘‘The Delivery’ - Twin 1The Delivery’ - Twin 1

Encourage active pushing Encourage active pushing

Semi-recumbent position Semi-recumbent position once T1 crowningonce T1 crowning

Episiotomy as necessaryEpisiotomy as necessary

Clamp & mark cord T1Clamp & mark cord T1

Ventouse or forcepsVentouse or forceps

‘‘The Delivery’ - Twin 2The Delivery’ - Twin 2

ECV

versus

Breech delivery

versus

Internal podalic version

Palpate lie immediately after delivery T1

‘ ‘ The Delivery’ - Twin 2The Delivery’ - Twin 2

Start syntocinon infusion Start syntocinon infusion once T2 cephaliconce T2 cephalicEscalate dose at 5 minute Escalate dose at 5 minute intervalsintervalsAwait contractions & PP to Await contractions & PP to stabilized above pelvisstabilized above pelvisARMARMFSE if poor external CTGFSE if poor external CTGVentouseVentouseBreech extractionBreech extraction?Delivery interval?Delivery interval

Combined vaginal-abdominal deliveryCombined vaginal-abdominal deliveryMisfortune or mismanagement?Misfortune or mismanagement?

Increasing incidence Increasing incidence 1-15% LSCS T21-15% LSCS T2

Higher rate elLSCS in Higher rate elLSCS in twinstwins LSCS for T2LSCS for T2 Operator experienceOperator experience Some management Some management

issuesissues

JustifiedJustified Failed version in Failed version in

transverse lietransverse lie SROM-shoulder SROM-shoulder

presentationpresentation Cord prolapse Cord prolapse

(especially prems)(especially prems) Large T2Large T2 ?Fetal distress with ?Fetal distress with

high presenting parthigh presenting part

Delayed delivery intervalDelayed delivery interval

Caution:Caution:isolated case reportsisolated case reports

publication biaspublication bias

Consideration:Consideration:gestation gestation

chorionicitychorionicity

maternal informed maternal informed consentconsent

Delayed delivery intervalDelayed delivery interval

48 twin pregnancies48 twin pregnancies

40/96 surviving 40/96 surviving infants infants (39=T2)(39=T2)

Interval 3 - 143 daysInterval 3 - 143 days

mean 44.8 daysmean 44.8 days

No consensus on No consensus on treatment strategytreatment strategy

Obs & Gyn Survey 1999: 54,343-8

‘‘The delivery’ - third stageThe delivery’ - third stage

Active managementActive management

Syntocinon 5 units Syntocinon 5 units (IV or IM)(IV or IM) after delivery after delivery of second twinof second twin

Syntocinon infusion after delivery of Syntocinon infusion after delivery of placentaplacenta

UK birth rate of TripletsUK birth rate of Triplets

0

50

100

150

200

250

300

1982 1984 1986 1988 1990 1992 1994

Higher multiples-?chorionicityHigher multiples-?chorionicity

Can be:Can be: TrichorionicTrichorionic DichorionicDichorionic

TriamnioticTriamniotic

Diamniotic Diamniotic MonochorionicMonochorionic

Tri-amnioticTri-amniotic

Monoamniotic (rare)Monoamniotic (rare)

Scan earlyScan early

Scan oftenScan often