11/17/19

1

Complications and management of monochorionic twins

Joanne Stone, MD MSDirector, Maternal Fetal Medicine

Professor, Obstetrics, Gynecology and Reproductive Sciences

Icahn School of Medicine at Mount Sinai

• I have no financial disclosures

Complications and management of monochorionic twins

Joanne Stone, MD MSDirector, Maternal Fetal Medicine

Professor, Obstetrics, Gynecology and Reproductive Sciences

Icahn School of Medicine at Mount Sinai

Monochorionic complications• Fetal loss• Fetal anomalies• Twin Twin Transfusion Syndrome (TTTS)• Selective Intrauterine Growth Restriction (sIUGR)• Twin Anemia Polycythemia Syndrome (TAPS)• Twin Reversed Arterial Perfusion (TRAP)• Monoamniotic Monochorionic Twins (MA/MC, MoMo)• Conjoined twins• High-order MC multiples• Death of one twin

Incidence

• Rate of spontaneously-conceived monozygotic twinning is constant: 3-5/1000 deliveries

• 30% of spontaneous twins are MZ• 2/3 of MZ twins are monochorionic• 20% of spontaneous twins are MC

Dizyotic(2/3):Maternal age (FSH)GeneticsART

Monozygotic (1/3):0.4 – 0.45% following non-stimulated in vivo conceptionMZ twinning increased after ART: <1%

75%

25%

11/17/19

2

Dating a twin pregnancy

• Use known date of conception if ART used• Ideally date CRL at 11+0 – 13+6 weeks• For spontaneous twins, larger CRL should be

used

ISUOG guidelines Ultrasound Obstet gGnecol 2016

• CRL discordance ≧ 10% or NT ≧ 20% require MFM discussion, detailed US and karyotype – For MCDA: NT Found in 25% MC twins and risk

early IUD or development TTTS > 30% but poor PPV and NPV

• Establishing Chorionicity– Diagnosis best in 1st trimester

• 98% accurate– Single placenta, T sign, membrane thickness < 1.5-2

mm

*Maruotti et al Eur J Obstet Gynec and Reprod Bio 2016 , **ISUOG guidelines Ultrasound Obstet gGnecol 2016

Follow-up after diagnosing MC twins

• MFM consultation• US every 2 weeks– MVP (maximum vertical pocket) to assess amniotic

fluid– Bladder– Umbilical artery and ductus venosus dopplers as

appropriate– MCA (middle cerebral artery dopplers)– Early and routine anatomy survey– Fetal echocardiograms

MC twins: single placenta

• ”chorio-angio-pagus” -(placenta-vascular-conjoined)

• Angioarchitecture explains pathophysiology behind unique complications and reasoning for management

• Explains how both are affected by complications

11/17/19

3

Diseases associated with unbalanced intertwin blood flow

• Twin-twin transfusion syndrome (TTTS)• Twin anemia polycythemia sequence (TAPS)

Diseases association with unequal partitioning of placenta

• Selective IUGR (FGR)• Can have both TTTS and sIUGR co-existing

IUGR twin

AGA twin

Unbalanced AV anastomoses and partitioning

TTTS TAPS

TTTS and TAPS

sIUGR

TTTS and sIUGR

TTTS and sIUGR TTTS and sIUGR and TAPS

Adapted from Dr Stephen Emery NAFNET

• Majority are uncomplicated

• 10 - 15% have TTTS

• 3% have spontaneous TAPS

• 15% have sIUGR– Unbalanced division of the placenta -> sIUGR

• Can have combination of unbalanced intertwin blood flow and unequal placental share

TTTS

• Accounts for about half of all deaths in MC twins• 70-100% loss rate – esp early severe disease• High neurologic morbidity in survivors (10-30%)

Lewi L AJOG 2008, Berghella V JRM 2001,van Hetern CF, Obstet Gynecol 1998

11/17/19

4

TTTSImbalance of A-V anastomoses in one direction – donor “transfuses”

volume to recipient

Dx: twin poly-oligo ( MVP ≤ 2cm, ≥ 8cm)

Recipient: polyuria, hypervolemia, distended bladder, HTN, cardiac hypertrophy and failure, abnormal arterial and/or venous Dopplers

Donor:hypovolemia, oliguria, collapsed bladder, IUGR, abnormal umbilicalartery Dopplers

Ultrasound findings in TTTS

• 1st trimester– CRL discordance– NT > 95th %ile or discordance >20%– Reversal or absence of ductus venosus A wave

• 2nd trimester findings– Abdominal circumference discordance–Membrane folding– Velamentous placental cord insertion in donor

TTTS Quintero Staging

Quintero RA. J Perinatol 1999, Stamillo AJOG 2010, Simpson L. AJOG Jan 2013

Some centers incorporate fetal echocardiography (recipient cardiomyopathy) into staging

TTTS Management• Delivery• Expectant management– majority stage I remain stable or regress– High perinatal mortality in stage III or higher

• Serial amnioreduction• Laser photocoagulation– Superior to AR in RCT– Treatment of choice for dual survival

• Selective termination of one fetus• Pregnancy termination

Senat MV NEJM 2004

TTTS outcomes with laser therapy

• 85% chance 1 survivor• 65% chance 2 survivors• 54% chance donor demise in Stage III with

abnormal Dopplers and sIUGR• 8% chance neurologic morbidity of survivors• Mean GA delivery – 33 weeks

Senat MF NEJM 2005, Chmiat RH AJOG 2011

11/17/19

5

NAFNet: what to do about stage I

• Multicenter retrospective observational study• 124 cases stage I TTTS• Expectant mgmt. vs. AR vs Laser• Risk factors for progression• Outcome data– Good: 2 survivors≧ 30 weeks–Mixed: Single survivor or delivery 26-29.9 weeks– Poor: Double fetal demise or delivery < 26 weeks

AJOG 2016

Column1

progress loss regress st able

60%

Progress/lost:50% poor outcome

8%

22%

10%

Regress/stable:Good outcome

Expectant management group

• Average of 11 days until change in status (regress, progress, termination, etc)

• No factors at diagnosis predictive of disease outcome• AR or laser protected against no survivors• Laser protected against poor outcome

TAPS(Twin Anemia Polycythemia Sequence)

• Large inter-twin Hb difference w/o AF discordance

• Small unidirectional unbalanced AV anastomoses near perimeter of placenta

• Incidence:– 3-6% previously uncomplicated 3rd

trimester MC/DA twins vs 13% after laser therapy

– Usually diagnosed > 26 weeks• DX: MCA-PSV dopplers:

• MCA PSV > 1.5 MoM in donor and < 0.8 MoM in recipient

TAPS Staging SystemStage Characteristics

I MCAPSV > 1.5 MOM and < 1.0 MOM, no compromise

II MCAPSV > 1.7 MOM and < 0.8 MOM, no compromise

III Stage I or II + cardiac compromise (severely abnormal dopplers)

IV Hydrops of donor

V Demise of 1 or both fetuses after diagnosis of TAPS

Stagelle f. Feta; Doagm Tjer 2010

Management and Outcomes of TAPS• Depends of timing and severity and

GA– Delivery– Expectant management– Selective termination– Intrauterine transfusion – Partial exchange transfusion– Laser

• Outcomes in spontaneous TAPS– 49 cases mc twins with spont

TAPS– 71% antenatal diagnosis

• 57% fetal therapy (IUT/PET, laser, selective feticide)

– 53% donors also had severe FGR vs 8% recipients

– Long term neurodevelopmental outcomes in 74 TAPS survivor at median of 4 years:• NDI in 44% donors and 18%

recipients• Severe NDI in 9% donors and 3%

recipients• Severe anemia and GA delivery

were independent risk factors for NDI

Tollenaar et al Ultrasound Obstet Gynecol 2019

11/17/19

6

Monochorionic complications: sIUGR

• Disproportionate placental partitioning• Incidence: 12 - 25% MC twins• Diagnosis

– EFW < 10th %ile in smaller twin– Significant growth discordancy (≥25%)

even at EFW > 10th %ile– Increase risk adverse outcomes

• Increase in perinatal loss and adverse neurologic complications– 20% fetal demise (smaller twin)– 35% neurologic morbidity (larger twin)

Graticos E UOG 2004

Classification, Outcomes and Management of sIUGR

Type Umbilical artery dopplers

Un-expected IUFD of either

Neurologic complic.

In-uterodeterioration

Average dis-cordance

GA delivery

monitor

I 2-4% <5% rare 29% 35w Weeklydopplers

II 0 – 30% 14% 90% 38% 32w DopplersSel. TermPTD, laser

?

III 15% in smaller

twin

15-40% 11% 36% 31-32w DopplersSel term

Laser?

Gratacos Ultrasound Obstet and Gynecol 2007, Ishti et al Fetal Diag 2009, Valsky et al Sem Fetal and Neon Med 2010, Johnson, A personal communication

Normaldoppler

PersistentAEDF/REDF

intermittentAEDF/REDF

Intra-uterine demise

Neonatal death

Intact survival

Type I sFGR expectant 3.1% 97.9%

Type I sFGR laser 16.7%

Type I sFGR selective red 0% 100%

Type II sFGR expectant 16.6% 6.4% 89.3%

Type II sFGR laser 44.3% 100%

Type II sFGR selective red 5% 3.7% 90.6%

Type III sFGR expectant 13.2% 6.8% 61.9%

Type III sFGR laser 32.9% 100%

Type III sFGR selective red 0% 5.2% 98.8%

Exp mgmt. best

Laser or SR may be better at previableGA in severe cases to protect survivingtwin from demise or neurologicimpairment

Townsend et al Ultasound Obstet Gynecol 2019

TRAP(Twin Reversed Arterial Perfusion)

Incidence: rare – 1/35,000 deliveriesDue to patent vascular anastomosesDiagnosis: Doppler ultrasound of Acardiac fetus’ umbilical cord shows arterial blood flowing toward the acardiac twin

• Early loss of 1 of a mc twin pair with patent anastomoses perfusing other?

• Twin with absent heart (acardiac) is perfused by co-twin (pump)

• Deoxygenated blood from pump twin leads to variable growth of acardiactwin

• Acardiac twin – high-flow, low resistance vascular bed

• Pump twin at risk of cardiac decompensation and demise (50%)

Management• Sonographic markers for poor

prognosis– Ratio of acardiac twin to pump twin

• L x W x H X 0.52 (formula for volume of a sphere) of acardiac/wt pump > 50%

– Polyhydramnios– Pump twin with cardiac failure with

abnormal dopplers– Increase in size of pump twin (AC of

acardiac/pump >1.0)• Expectant

• 30% loss rate between 1st trimester diagnosis and 2nd trimester intervention

• Early intervention– Occlusion of vascular connections

(RFA, laser)

11/17/19

7

Monoamniotic (MA) twins

• 1 in 10,000 pregnancies

• Greater number of superficial and deep

anastomoses = ?protective

• Risks:

– Cord entanglement

– Congenital anomalies

– PTD

– TTTS (rare)

• Perinatal Mortality

§ Past - PNM 30-70%

§ Recently - PNM 10-20%

§ 4% > 24 weeks if no structural anomalies,

TTTS, TRAP

• Inpatient management?

• Delivery 32-34 weeks – C/S

• Mode of delivery = cesarean

Ultra Obstet Gyn 2000;16(3):223, Acta Obstet Gyn Scand 2005;84(5):432, ltra Obstet Gyn 2006;28:681 Prefumo et al Pren Dx 2015

• Multinational cohort study 2010-2017• Non-anomalous uncomplicated MO/MO twins with 2 live

fetus at 26 weeks included• 10 centers inpatient, 12 centers outpatient• Primary outcome IUFD• 195 women (290 fetuses)• Results

– Overall perinatal loss rate 10.8%– 4 women (5/3%) inpt and 15 women (12.5%) outpt IUFD– Peak fetal death rate 4.3% occurring at 29 weeks– From 32 – 36 +6 weeks no fetal/neonatal deaths– No difference in in-patient or out-patient groups

Conjoined twins

• Very rare: 10.2/million births

• 18% prenatally-diagnosed fetuses survive

• Increase rate of structuralanomalies

• Outcomes depend on which organs are shared

Discordant anomalies• Structural anomalies more common in MC twins

(6-8%)• Only 20% are concordant for anomaly• Monozygotic twins are NOT identical– Post-zygotic mutation– Variations in gene expression– Asymmetric x-chromosome inactivation– Parental imprinting– Discordant gene methylation– Vascular accidents

Options

• Expectant• Termination• Umbilical cord occlusion– Bipolar cord coagulation– Radiofrequency ablation (RFA)

RFA

11/17/19

8

RFA: technique• IR suite• IV sedation• US guidance• Skin prep• Bilateral grounding pads• Local anesthesia• Skin/fascia incised with 11 blade

scalpel• LeVeen needle inserted into fetal

abdomen just at/above cord insertion

• Prongs deployed• 60W energy delivered for about

60seconds; power increased by 20W in 60 second intervals to 120W or when impedance dropped

• Cessation of vascular flow within cord confirmed

• Pt observed post-op for several hours

RFA outcomes – for various etiologies

• About 15% PPROM (up to 25%)• Miscarriage survivor about 5%• Neurologic morbidity survivor about 5%• Live birth rate about 80%• Mean GA delivery 33-36 weeks

Kumar et al AJOG 2014, Lee et al Fetal Diagn Ther

Death of one twin

• Bleeding of surviving twin into demise twin– Hypotension, hypovolemia, anemia, hypoxia, acidosis– 15% risk demise of co-twin– 25-35% risk severe neurologic morbidity in survivor

• Management– Immediate deliver after unwitnessed twin death – no

benefit– Expectant management– Fetal brain MRI’s of survivior

Demise of co-twin

• Retrospective observational study at UCSF• 21 MC twins (none had laser/RFA)• Mean GA demise: 19 6/7 w (12 4/7 – 26 6/7)• Interval to MRI: 4 3/7 w (0-12 1/7)• 41% associated with TTTS• Abnormal findings in 7 cases (33%)• Majority had normal ultrasound

Jelin et al AJOG 2008

conclusions

• Establish chorionicity early• Every 1-2 week surveillance• Anatomy surveys and echocardiography• Deliver uncomplicated MC twins around 36

weeks

Thank you