TWIN PREGNANCYTWIN PREGNANCY

Ahmad Kurdi SyamsuriAhmad Kurdi Syamsuri

TWIN PREGNANCYTWIN PREGNANCY

Multiple pregnancy rates vary world Multiple pregnancy rates vary world widewide

InsInsideidence of monozygotic twin is nce of monozygotic twin is relatively constantrelatively constant : 3 – 5/1000 births : 3 – 5/1000 births

Dizygotic twinning rates vary by age, Dizygotic twinning rates vary by age, parity, ethnic group and assisted parity, ethnic group and assisted reproductionreproduction : 1,3 – 49/1000 births : 1,3 – 49/1000 births

IncidenceIncidence

• 1.4 per 100 birth in Korea Korean birth certificate,

1996

Multiple pregnancy rates

2.1%

3.7%4.3%

3.9%

2.4%1.9%

2.3%2.4%

0.0%

1.0%

2.0%

3.0%

4.0%

5.0%

1997 1998 1999 2000 2001 2002 2003 2004

• More than 3 % in US Martin and colleques, 2002

2007

Twins - ChorionicityTwins - Chorionicity

100 Twins100 Twins

Dizygotic Dizygotic MonozygoticMonozygoticn = 70n = 70 n = 30n = 30

DichorionicDichorionic Monochorionic Monochorionic

n=80n=80 n=20n=20

Types and Genesis of TwiningTypes and Genesis of Twining

Dizygotic Monozygotic

Dichorionic Diamnionic

Dichorionic Diamnionic

Monochorionic Diamnionic

Monochorionic Monoamnionic

Conjoined

By timing of division

< 3 day 4- 8 day > 8 day > 12 day

Superfetation

Superfecundation

“Vanishing twin”

Determination of ChorinicityDetermination of Chorinicity6 weeks6 weeks1. If one fetus in two chorionic sacs1. If one fetus in two chorionic sacs DCDC2. If two fetus in one chorionic sac2. If two fetus in one chorionic sac MCMC3. If as in 2. and one yolk sac3. If as in 2. and one yolk sac

ConjoinedConjoined

8 weeks8 weeks 4. If as in 2. and separate amniotic sacs4. If as in 2. and separate amniotic sacs

MC/DAMC/DA5. If as in 2. and one amniotic sac5. If as in 2. and one amniotic sac

MC/MAMC/MA

Determination of ChorinicityDetermination of Chorinicity

10-14 weeks10-14 weeks

““Twin peak” or “Lambda sign” - projection of Twin peak” or “Lambda sign” - projection of placental tissue into the inter-twin membraneplacental tissue into the inter-twin membrane : : DCDC

>14 weeks>14 weeks

Count placentaeCount placentae

Sex of fetusesSex of fetuses

?Dividing membrane >2mm?Dividing membrane >2mm

MATERNAL RISKS WITH MATERNAL RISKS WITH TWINSTWINS

Increased minor complaints of Increased minor complaints of pregnancypregnancy

Increased risk of miscarriageIncreased risk of miscarriage Increased anaemia, pre-term deliveryIncreased anaemia, pre-term delivery HypertensionHypertension Antepartum HaemorrhageAntepartum Haemorrhage

MATERNAL RISKS WITH MATERNAL RISKS WITH TWINS (contd.)TWINS (contd.)

Hydramnios Hydramnios Need for hospitalisationNeed for hospitalisation Single fetal death in twinsSingle fetal death in twins Operative DeliveryOperative Delivery Caesarean SectionCaesarean Section Postpartum HaemorrhagePostpartum Haemorrhage

Pre-term Labour/DeliveryPre-term Labour/Delivery

Pre-term birth (<37 weeks)Pre-term birth (<37 weeks) 43.6%43.6%

Very pre-term (<32 weeks)Very pre-term (<32 weeks) 6.0% 6.0%

HypertensionHypertension

Pre-eclampsia – 5 times more likely Pre-eclampsia – 5 times more likely in twin pregnancy.in twin pregnancy.

Perinatal MortalityPerinatal Mortality

Up to 10 times higher than singletonsUp to 10 times higher than singletons

Single Fetal Death in TwinsSingle Fetal Death in Twins

Early single demiseEarly single demise : trim I : trim I• Relatively commonRelatively common• No No Increased risk of fetal loss in suviving Increased risk of fetal loss in suviving

twintwin

Single Fetal Death in TwinsSingle Fetal Death in Twins

Late single fetal demiseLate single fetal demise Inceased risk of death of Inceased risk of death of

surviving twin of 20%surviving twin of 20% Chorionicity very importantChorionicity very important

Monoamniotic TwinsMonoamniotic Twins

1% of monozygotic pregnancies1% of monozygotic pregnancies Mortality up to 50%Mortality up to 50% Cord entanglementCord entanglement

Twin-Twin TransfusionTwin-Twin Transfusion

Monochorionic twinsMonochorionic twins Vascular AnastomosesVascular Anastomoses Up to 30% Up to 30% Mortality 30%Mortality 30% Severe morbidity in survival Severe morbidity in survival

2. Twins with two separate placental 2. Twins with two separate placental masses can still be masses can still be monochorionicmonochorionic and and therefore have vascular anastomosestherefore have vascular anastomoses

American Journal of Obstetrics and Gynecology 2006 2006

pathogenesis pathogenesis of bipartite of bipartite placentation placentation in MC in MC twinning twinning ：： not clearnot clear

Dichorionic TwinsDichorionic Twins

Management in specialised unitManagement in specialised unit Scan for growth monthlyScan for growth monthly Aim for vaginal deliveryAim for vaginal delivery

Monochorionic TwinsMonochorionic Twins

Specialised clinicSpecialised clinic Scan fortnightlyScan fortnightly Aim for vaginal deliveryAim for vaginal delivery

•Women who are offered ART should be provided with adequate counseling about the increased risk of multiple pregnancy and the potential complication

Management in Pre-Pregnancy Management in Pre-Pregnancy

•All pregnant women should be advised to take periconceptual folate supplementation to reduce the risk of fetal neural tube defects

Ultimate goalsUltimate goals

– to prevent the delivery of markedly preterm fetusesto prevent the delivery of markedly preterm fetuses– to identify growth restriction in 1 or both fetuses to identify growth restriction in 1 or both fetuses – to deliver the fetuses atraumaticallyto deliver the fetuses atraumatically– to have expert anesthesia and neonatal care availableto have expert anesthesia and neonatal care available

Antepartum ManagementAntepartum Management

Determination of chorionicity Determination of chorionicity

Best performed in the first trimester with Ultrasound1. Numbers of G-sac2. Detection of the ‘lambda sign’ or ‘twin peak’ ; best seen between 10-14 weeks, disappear after 20 weeks3. Measurement of membrane thickness, using a cut-off value of 2 mm

Antepartum ManagementAntepartum Management

Describe as DCDA / MCDA / MCMA twin

Antenatal screeningAntenatal screening

Increased Increased hypertensive disordershypertensive disorders in pregnancy in pregnancy – 5 times greater in primigravid women5 times greater in primigravid women

– 10 times greater in multiparous women than singleton pregnancy10 times greater in multiparous women than singleton pregnancy

-> -> frequent antenatal attendance allows the early detection of hypertensionfrequent antenatal attendance allows the early detection of hypertension

Gestational diabetes screening; Gestational diabetes screening; conflicting evidenceconflicting evidence to support the practice to support the practice

Increased risk of Increased risk of antepartum hemorrhageantepartum hemorrhage from both placenta previa and from both placenta previa and abruptionabruption

Antepartum ManagementAntepartum Management

Routine fetal anomaly ultrasound at 18–20 weeks

•Twins have an increased risk of congenital abnormalities ->midtrimester ultrasound examination between 18 and 20 weeks gestation.

; A retrospective review of 245 women with a twin pregnancy -> congenital malformation in 4.9% of cases

Edwards M, Ultrasound in Obstetrics and Gynecology, 1995

Antepartum ManagementAntepartum Management

• Cervical length of less than 25 mm at 24 weeks in twins; ; predictor of spontaneous preterm birth at < 32 weeks (OR 6.9), < 35 weeks (OR 3.2), and < 37 weeks (OR 2.8) ; its clinical usefulness as a routine evaluation is questionable because of the lack of proven treatments affecting outcome

1. Cervical assessment

2. Fetal fibronectin

•The presence of fetal fibronectin in cervical secretions ; ; positive test at 28 weeks to predict preterm birth before 35 weeks => 50% sensitivity, 92% specificity, 62.5% positive predictive value, 87.3% negative predictive value

•it is unclear if this knowledge can result in effective interventions that could reduce preterm labor and birth

Antepartum ManagementAntepartum Management

Preterm labor

Labor and DeliveryLabor and Delivery

Timing of birth

• The lowest risk of perinatal mortality and morbidity; between 36 and 38 weeks

After 38 weeks gestation, the perinatal death rate and intrauterine growth restriction of twin pregnancies increase substantially

In a single RCT from Japan, Women were randomised at 37 weeks gestation either to induction of labor or to continued expectant management; No statistically significant differences

• The ideal time of delivery for an uncomplicated twin pregnancy is still uncertain. However, the literature appears to support delivery by 38 weeks of gestation

Mode of birth•Women with a twin pregnancy are more likely to give birth by caesarean, with gestational age and fetal presentation influencing this decision

•First twin vertex/second twin vertex•the most common presentation of twins•the general recommendation is for vaginal birth, even for infants of estimated very low birthweight (less than 1500 g)

•First twin vertex/second twin non-vertex

•no consensus as to the most appropriate mode of birth•The only small RCT, planned vaginal or planned caesarean birth showed no differences in neonatal outcome•For the second non-vertex twin of birthweight less than 1500 g, some reports recommend caesarean birth to reduce the risk of birth trauma

•First twin non-vertex• Caesarean section is often performed

Antepartum ManagementAntepartum Management

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