the terrible twos.ppt -...

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The Terrible Twos Complications of Twinning

Paula J. Woodward, M.D.

Disclosure

Medical Editor Amirsys Content, Elsevier

Learning Objectives

Thoroughly understand how to determine chorionicity and amnionicity and their impact on pregnancy management and outcomes

Twins

Twins account for 1.1 % of pregnancies in USA but 10% of perinatal morbidity and mortality Perinatal mortality 4 to 6x singleton rate

What matters? Presence of anomalies

Growth discrepancy

Chorionicity!

Probability of 2 live births

Normal scan at 6 weeks Dichorionic 76%

Monochorionic 39%

Normal scan at 12 weeks Dichorionic 96%

Monochorionic 74% Blastocyst “buries” itself

into endometrium

Forms gestational sac

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Decidua is endometrium in pregnancy

Intradecidual sac sign - visualized 4 – 4.5 wks


Double decidual sac sign Intradecidual sac sign


Decidua basalis

Decidua capsularis

Decidua parietalis

Double decidual sac sign

DB


Decidua basalis

Decidua capsularis

Decidua parietalis


DC


Decidua basalis

Decidua capsularis

Decidua parietalis


DP


Decidua basalis

Decidua capsularis

Decidua parietalis


DP

DC

DB

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DP

DC

DB

DCDP

Chorion is from embryonic trophoblast

Chorionic sac = Gestational sac

Chorion is from embryonic trophoblast

Chorionic sac = Gestational sac Smooth chorion

Villous chorion (chorionic fronduosum)

Smooth chorion

Villous chorion (chorionic fronduosum)

Visualized at 5 – 5.5 weeks

Normal YS < 5 mm

Yolk sac

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Visualized at 5 – 5.5 weeks

Normal YS < 5 mm

Yolk sac Visualized 6 – 6.5 wks

Embryo

Diamond Ring Sign

Embryo Yolk Sac

Visualized 6 – 6.5 wks Embryo

Double Bleb Sign

7-9 Weeks

10-13 wks

Embryo becomes fetus at 10 wks

Organogenesis complete

Many anomalies identifiable

Amnion and chorion not yet fused

Decidua Parietalis Decidua Capsularis

Decidua Basalis Villous Chorion

Smooth Chorion

Amnion

Placenta

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Multiple Gestations

Types of Twinning

Dizygotic (70%) 2 eggs

Incidence increases with age, parity, maternal family history, assisted reproduction, race (African-American > Caucasian > Asian)

Monozygotic (30%) Single egg

Incidence about 1/250, independent of race, age, parity

Multiple Gestations

# of chorions equals # of placentas sharing is bad

risk for twin/twin transfusion

# of amnions equals # of separate sacs sharing is really bad

risk for cord accidents

Multiple Gestations





Multiple Gestations





Multiple Gestations





Multiple Gestations





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Dizygotic TwinsDizygotic must be dichorionic (2 placentas)

and diamniotic (2 amniotic sacs)

4.5 weeks 5.5 weeks

7 weeks 2nd trimester

Twin Peak Sign

When present 94% sensitivity for predicting dichorionicity

If absent may still dichorionic

2nd trimester

1st Trimester

2nd Trimester

ThickThin

Hmm…

No definition of “thick” and “thin” at any gestational age Monozygotic Twins

1/3 are Dichorionic/Diamniotic (30%) cleavage by day 3

2/3 are Monochorionic/Diamniotic (60-65%) cleavage day 4-8

Monochorionic /Monoamniotic (5-10%) cleavage >8 days

Conjoined twins (< 1%) cleavage >14 days

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Dichorionic Diamniotic Monochorionic Diamniotic

MonochorionicMonoamniotic

Monochorionic Diamniotic

5.5 weeks

Generally, number of yolk sacs = number of amnions

Generally, number of yolk sacs = number of amnions

5.5 weeks 7.5 weeks

Monochorionic Diamniotic Monochorionic Monoamniotic

Monochorionic Monoamniotic Monochorionic Monoamniotic

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Monochorionic Monoamniotic

2013 literature review on outcome of 228 fetuses (i.e. 114 pairs) with cord entanglement Overall survival 88.6%

Perinatal mortality 11.4%

“Cord entanglement is a minor complication of monoamniotictwin pregnancies“

Prematurity and congenital anomalies have far more significant impact on outcomes

Rossi AC et al: Impact of cord entanglement on perinatal outcome of monoamniotic twins: a systematic review of the literature. Ultrasound Obstet Gynecol. 41(2):131-5, 2013

Monochorionic Monoamniotic

Conjoined Twins

Difficult diagnosis in first trimesterMust follow all monochorionic monoamniotic twins closely

Conjoined Twins

Difficult diagnosis in first trimesterMust follow all monochorionic monoamniotic twins closely

trichorionic, triamniotic dichorionic, triamniotic

monochorionic, triamnioticdichorionic, diamniotic

A bad day in ultrasound

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Monochorionic Issues

Twin-twin transfusion syndrome (TTTS)

Twin anemia polycythemia sequence (TAPS)

Twin reverse arterial perfusion (TRAP)

Fetus-in-fetu

Twin demise

Twin-Twin Transfusion Syndrome (TTTS)

Placental anastomosis result in artery-to-vein shunting

Donor (pump) twin Sending blood to co-twin instead

of to placenta

Less blood to placenta less coming back

Oligemia decreased renal perfusion oligohydramnios

Recipient twin Gets “extra” blood from co-twin

volume overload

Lots of blood to kidneys lots

of urine polyhydramnios


Not all anastomoses created equal

Present in virtually all monochorionic pregnancies

Artery-to-artery Superficial and bidirectional

Protective

Vein-to-vein Superficial and bidirectional

Artery-to-vein Deep and unidirectional


Not all anastomoses created equal

Present in virtually all monochorionic pregnancies

Artery-to-artery Superficial and bidirectional

Protective

Vein-to-vein Superficial and bidirectional

Artery-to-vein Deep and unidirectional


Fluid discordant: oli/poly Polyhydramnios: Deepest fluid

pocket > 8cm

Oligohydramnios: Deepest fluid pocket < 2cm

“Stuck” twin Severe oligohydramnios

Fetus is in fixed position

May not see membrane

EFW discordance >20%

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Fluid discordant: oli/poly Polyhydramnios: Deepest fluid

pocket > 8cm

Oligohydramnios: Deepest fluid pocket < 2cm

“Stuck” twin Severe oligohydramnios

Fetus is in fixed position

May not see membrane

EFW discordance >20%

TTTS: Quintero Staging

Stage 1: Donor bladder visible, normal Doppler

Stage 2: Donor bladder empty, normal Doppler

Stage 3: Donor bladder empty, abnormal Doppler

Stage 4: Hydrops in recipient

Stage 5: Demise of one or both













Tricuspid regurgitation

Cincinnati system incorporates cardiovascular profiling score DV/UV/UA Doppler

Cardiothoracic ratio

Ventricular systolic function

Atrioventricular valve regurgitation

Strongest predictor of recipient demise is echocardiographic evidence of cardiomyopathy

TTTS: Staging 20 weeks

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TTTS: Natural History

Complicates 10-20% of monochorionic pregnancies

70-90% reported mortality of untreated Donor dies first in 2/3 of cases

Morbidity common in survivors Neurologic (especially in co-twin demise)

Cardiac

TTTS: Treatment

Early delivery

Serial amnioreductions

Septostomy

Laser coagulation of shunt vessels

Laser Coagulation Corrects hemodynamic

imbalance (“dichorionizing”)

Overall survival 66%

70% recipient

60% donor

Complex protocol requiring serial scans, Doppler, echocardiography and MRI

Laser Coagulation Corrects hemodynamic

imbalance (“dichorionizing”)

Overall survival 66%

70% recipient

60% donor

Complex protocol requiring serial scans, Doppler, echocardiography and MRI

TAPS: Twin Anemia Polycythemia Sequence

Most commonly seen after laser for TTTS but can occur spontaneously Residual small artery-vein

anastomsis

No fluid discrepancy

Intertwin shunt

Hb discrepancy tracked by MCA Doppler MCA PSV > 1.5 MoM in one twin

MCA PSV < 0.8 MoM in co-twin

Treatment is supportive

Transfuse for severe anemia

Discordant Twins

Not the same as TTTS No unbalanced vascular anastomoses

> 20% difference in EFW

> 20 mm difference in AC

Ratio of AC < 0.93

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Southwest Thames Obstetric Research Collaborative (STORK)

EFW discordance of >25% is the best predictor of perinatal mortality Irrespective of chorionicity or individual fetal size

(i.e. does not have to growth restriction) Discordant growth in monochorionic twins should

always be considered pathological even if both grow appropriately

D’Antoio etl al. Weight discordance and perinatal mortality in twins Ultrasound in Obstetrics & Gynecology June 2013 Volume 41, Issue 6

Look for marginal/velamentous cordwith discordant twins

Always document placental postion and umbilical cord insertion 17 weeks 32 weeks

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Twin Reversed Arterial Perfusion (TRAP)

Placental anastomosis result in arterioarterial shunting

Recipient twin (acardiac) Perfused with co-twin’s

deoxygenated blood

Blood flow into fetus via arteries (i.e. reversed flow in umbilical cord)


Recipient twin (acardiac) UA flow preferentially

into internal iliac and lower extremities

Poor or no development of heart or cranial structures

Dysmorphic edematous mass usually with recognizable torso and lower extremities


Recipient twin (acardiac) UA flow preferentially

into internal iliac and lower extremities

Poor or no development of heart or cranial structures

Dysmorphic edematous mass usually with recognizable torso and lower extremities

Acardiac arterial anastomotic vessel

A

B

Arterial flow toward fetus is diagnostic

Pump twin TRAP twin

Also evaluate ductus venosus flow in donor

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Often shows rapid growth

Twin BTwin A

Head

11 weeks

17 weeks

Twin B

Twin A

25 weeks

Twin B

Twin A

Head

Twin B

25 weeks

Twin A

Head

Twin B

Risks to pump (normal) twin High output heart failure

Hydrops

Polyhydramnios – often severe

Growth restriction

Prematurity

Death 10-70% (av. 50% most series)

Neurologic, cardiovascular sequelae in survivors

Treatment Options

Aim is to preserve normal twin Expectant management

Small/ slow growth of acardiac No hydrops/ CHF in pump twin Requires very close monitoring

Interruption of cord blood flow Surgical ligation, laser

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Treatment Options Radiofrequency ablation (RFA)

RFA needle device introduced into acardiac abdomen at level of umbilical artery and vein

RFA energy applied until cessation of blood flow noted in acardiac

TWIN A: Pump twin

TWIN B: “Acardiac” RFA of reverse-perfused twin at 18 weeks

Treatment Options Radiofrequency ablation (RFA)

RFA needle device introduced into acardiac abdomen at level of umbilical artery and vein

RFA energy applied until cessation of blood flow noted in acardiac

A

B

Mono-mono twins stillborn at 24 weeks; demise of twin B (acardiac)

noted clinically at 16 weeks

Twin A Twin B

30 cm, 455 g 12 cm, 46 g

Mono-mono twins stillborn at 24 weeks; demise of twin B (acardiac)

noted clinically at 16 weeks

Fetus-in-Fetu Historically regarded as well-differentiated teratomas

Current thinking is parasitic twin Monochorionic, diamniotic twin incorporated into the body of

other twin early in development

Anastomoses between vitelline vessels

Surrounding capsule formed by amniotic membrane

Forms fluid-filled cavity

Axial skeleton surrounded by synchronous organ development around this axis

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AnteriorLeft foot with 6 toes, 3 fused

Right Foot with5 toes

Possible arm bud

3-vessel umbilical cord

Vertebral column

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Monochorionic Twin Demise

Twin “embolization” syndrome

More likely acute hypotensive episode in survivor causing hypoxic injury Brain

Kidneys

Heart

Brain Injury

November 23rd December 1st

Myocardial Injury

November 23rd December 1st

Take Home Points

The 1st person to scan the patient MUSTdetermine chorionicity and amniocity

Monochorionic pregnancies should be followed closely for complications

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References – The Terrible Twos: Complications of Twinning

Carter EB et al: The impact of chorionicity on maternal pregnancy outcomes. Am J Obstet Gynecol.

213(3):390.e1-7, 2015

Henry A et al: Pregnancy outcomes before and after institution of a specialised twins clinic: a

retrospective cohort study. BMC Pregnancy Childbirth. 15:217, 2015

Blumenfeld YJ et al: Accuracy of sonographic chorionicity classification in twin gestations. J Ultrasound

Med. 33(12):2187-92, 2014

Ratha C et al: An analysis of pregnancy outcome in dichorionic and monochorionic twins given special

antenatal and intranatal care: a four-year survey. J Obstet Gynaecol India. 64(4):255-9, 2014

Mcnamara HC et al: A review of the mechanisms and evidence for typical and atypical twinning. Am J

Obstet Gynecol. ePub, 2015

American College of Obstetricians and Gynecologists et al: ACOG Practice Bulletin No. 144: Multifetal

gestations: twin, triplet, and higher-order multifetal pregnancies. Obstet Gynecol. 123(5):1118-32, 2014

Stahr N et al: In utero and postnatal imaging findings of parasitic conjoined twins (ischiopagus

parasiticus tetrapus). Pediatr Radiol. 45(5):767-70, 2015

Burans C et al: 3-dimensional ultrasound assisted counseling for conjoined twins. J Genet Couns.

23(1):29-32, 2014

Mone F et al: Intervention versus a conservative approach in the management of TRAP sequence: a

systematic review. J Perinat Med. ePub, 2015

van Gemert MJ et al: Twin reversed arterial perfusion sequence is more common than generally

accepted. Birth Defects Res A Clin Mol Teratol. 103(7):641-3, 2015

Chaveeva P et al: Optimal method and timing of intrauterine intervention in twin reversed arterial

perfusion sequence: case study and meta-analysis. Fetal Diagn Ther. 35(4):267-79, 2014

Halling C et al: Neuro-developmental outcome of a large cohort of growth discordant twins. Eur J

Pediatr. ePub, 2015

Allaf MB et al: Does early second-trimester sonography predict adverse perinatal outcomes in

monochorionic diamniotic twin pregnancies? J Ultrasound Med. 33(9):1573-8, 2014

Johansen ML et al: Crown-rump length discordance in the first trimester: a predictor of adverse

outcome in twin pregnancies? Ultrasound Obstet Gynecol. 43(3):277-83, 2014

Rossi AC et al: Impact of cord entanglement on perinatal outcome of monoamniotic twins: a systematic

review of the literature. Ultrasound Obstet Gynecol. 41(2):131-5, 2013

Akkermans J et al: Twenty-Five Years of Fetoscopic Laser Coagulation in Twin-Twin

TransfusionSyndrome: A Systematic Review. Fetal Diagn Ther. 2015;38(4):241-53.

Simpson LL. What you need to know when managing twins: 10 key facts. Obstet Gynecol Clin North Am.

2015 Jun;42(2):225-39.

Dhillon RK et al:. Comparison of Solomon technique with selective laser ablation for twin-twin

transfusion syndrome: a systematic review. Ultrasound Obstet Gynecol. 2015 Nov;46(5):526-33

Mahalingam S, Dighe M. Imaging concerns unique to twin pregnancy. Curr Probl Diagn Radiol. 2014 Nov-

Dec;43(6):317-30.

Rossi AC, Prefumo F. Perinatal outcomes of twin anemia-polycythemia sequence: a systematic review. J

Obstet Gynaecol Can. 2014 Aug;36(8):701-7.

Chmait RH et al: Sequential laser surgery for twin-twin transfusion syndrome. Am J Perinatol. 2014

Sep;31 Suppl 1:S13-8.

De Lia JE, Kuhlmann RS. Twin-to-twin transfusion syndrome--30 years at the front. Am J Perinatol. 2014

Sep;31 Suppl 1:S7-12.

Peeters SH et al:. Fetal surgery in complicated monoamniotic pregnancies: case series and systematic

review of the literature. Prenat Diagn. 2014 Jun;34(6):586-91.

Simpson LL. Ultrasound in twins: dichorionic and monochorionic. Semin Perinatol. 2013 Oct;37(5):348-

58.

Arlikar JD et al:. Fetus in fetu: two case reports and review of literature. Pediatr Surg Int. 2009 Mar;25(3):289-92.

D'Antonio F et al:Southwest Thames ObstetricResearch Collaborative (STORK). Weight discordance and

perinatal mortality in twins: analysis of the Southwest Thames Obstetric Research Collaborative (STORK)

multiple pregnancy cohort. Ultrasound Obstet Gynecol. 2013 Jun;41(6):643-8.

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