Kenneth J. Moise, Jr., M.D.Professor of Obstetrics and GynecologyProfessor of Pediatric SurgeryMcGovern Medical School – UT Health Co-DirectorThe Fetal CenterChildren’s Memorial Hermann Hospital

Identification and Management ofTwin-Twin Transfusion

• Royalties for multiple chapters on red cell alloimmunization in UpToDate®

• Consultant to LFB Biotechnologies in development of synthetic Rhesus immune globulin

• Consultant to Momenta Pharmaceuticals in the development of immunomodulation for the treatment of HDFN

Disclaimers

• Describe the proper timing of determining the chorionicity of a twin gestation

• Describe the risks and benefits of laser therapy for the treatment of twin-twin transfusion syndrome.

Twin-Twin TransfusionObjectives

Organizational Recommendations

• The chorionicity of a multifetal gestation should be established as early in pregnancy as possible

• The optimal timing for determination of chorionicity by ultrasonography is in the late first or early second trimester

Diagnosis of Chorionicity

T sign

MonochorionicPlacenta

Lambda sign

DichorionicPlacenta

Diagnosis of Chorionicity

Multifetal Pregnancies Establish Chorionicity @ 10-14 Weeks

• “T” sign • Monochorionic

• Twin Peak (lambda) • Dichorionic

Take-home Message

There is NO diagnosis of twins

Monochorionic TwinsSurveillance

• Start at 16 weeks gestation• Evaluate MVP in both sacs and fetal bladders every

2 weeks • Anatomy scan at 20 weeks• Fetal echocardiogram

SMFM, Simpson. Am J Obstet Gynecol 2013;208:3-28

Monochorionic TwinsComplications

• Increased risk of anomalies (2.7X increased over dichorionic twins; 82% discordant)

• Death of a single twin (?)• Twin-twin transfusion (10 – 15%)• Selective IUGR (10 – 15%)• Twin anemia-polycythemia sequence (3 – 5%)• Acardiac twinning (TRAP sequence) (1%)

Risk of Death of a Monochorionic Twin

Monochorionic TwinsRisk of Single Demise

– Old theory of “bad humors” crossing to the live twin discounted– Acute hemodynamic changes the more likely etiology– No benefit from acute delivery

– 15% of cases associated with IUFD of co-twin• ↑ 5X over dichorionic twins

– 26% of survivors with neurologic sequelae• ↑ 5X over dichorionic twins

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Risk of in-utero death of affected twin

Fusi et al. Obstet Gynecol 1991;78:517-20Hillman et al. Obstet Gynecol 2011;118:928-40

↓ BP ↓ BP

SelectiveIUGR

Monochorionic TwinsSelective IUGR

Monochorionic TwinsSelective IUGR

• One twin with normal growth and amniotic fluid

• Second twin with IUGR (< 10% EFW with > 20% discordance in growth between twins) and oligo

• Related to unequal placental sharing

Monochorionic TwinsSelective IUGR

• Type 1: Normal diastolic UA flow (29%)

• Type II: Persistent AREDV (22%)

• Type III: iAEDV (49%)

134 cases (< 10% EFW)

Gratacos et al. Ultrasound Obstet Gynecol 2007:30:28-34

Monochorionic TwinsSelective IUGR

Gratacos et al. Ultrasound Obstet Gynecol 2007:30:28-34

Parameter Type 1 Type II Type IIIGest Age @ delivery 35.4 30.7 31.6Unexpected death

Larger twin 2.6% 0% 6.2%

Smaller twin 2.6% 0% 15.4%

Parenchymal damage

Larger twin 0% 3.3% 19.7%

Smaller twin 0% 14.3% 2.0%

Twin-twinTransfusionSyndrome

Monochorionic TwinsEpidemiology of TTTS

Dickinson et al. Am J Obstet Gynecol 2000;182:706-12Saunders et al. Am J Obstet Gynecol 1992;166:820-4

• Complicates 10% of monochorionic twins

• One in 58 twin pregnancies

• One in 4,170 pregnancies

• Presentation @ <25-26 weeks associated with a 90% perinatal mortality

Monochorionic TwinsDiagnostic Criteria

• Same sex• Single placenta• Thin dividing membrane (or “T” sign documented

in the first trimester)• Massive hydramnios/oligohydramnios> 8 cm vertical pocket @ <20 wks; >10 cm >20 wks< 2 cm vertical pocket in second sac

Monochorionic Twins/Pathophysiology of TTTS

ΑΑ

ΑV

DONOR

RECIPIENT

Monochorionic Twins/Pathophysiology of TTTS

Monochorionic Twins/TTTS Staging

Stage 1Donor MVP <2 cm;Recipient MVP >8-10 cm

Stage 2Absent bladder in donor twin; normal Doppler studies

14cm

Monochorionic Twins/TTTS Staging Stage 3

Normal

Umbilical Artery

Ductus Venosus

Umbilical Vein

Middle CerebralArtery

Abnormal

Recipient

Donor

Monochorionic Twins/TTTS Staging

Stage 5One or both fetuses have died

Stage 4

Monochorionic TwinsLaser for TTTS

• First performed by DeLia

• 3 cases at 18.5, 22 and 22.5 weeks’ gestation

• Delivery at 27 and 34 weeks for PPROM; third case delivered at 29 weeks due to pre-eclampsia

• 4/6 infants survived DeLia et al. Obstet Gynecol 1990;75:1046-53

Laser Photocoagulation

Monochorionic TwinsLaser vs. Amnio for TTTS

Laser AmnioreductionSurvival of one fetus 40% 26%

Survival of both fetuses 36% 26%

Survival of at least one fetus

76% 51%

GA at delivery 33.3 29.0

Alive w/o neurologic problems

52% 31%

Senat et al. N Eng J Med 2004; 351:136-44

Monochorionic TwinsStage I Outcome

Emery et al. Am J Obstet Gynecol 2016;215:346.e1-7

124 cases of Stage I TTTS

Good: 2 with delivery > 30 wks EGA

Mixed: 1 demise or delivery @ 26-29 wks EGA

Poor: dual demise or delivery < 26 wks EGA

Monochorionic TwinsCandidates for Laser for TTTS

• Stage II – IV TTTS• Stage I with one of the following Severe maternal discomfort due to polyhydramnios Short cervix Amnioreduction for travel onlyo Septostomy – unable to perform laser

Monochorionic TwinsLearning Curve of Laser

Papanna et al. Am J Obstet Gynecol 2011;204:218 e1-4

Laser Photocoagulation Outcome

Laser Photocoagulation Outcome

Laser Photocoagulation Outcome

Monochorionic TwinsComplications After Laser for TTTS

• Twin-anemia polycythemia sequence

• Reversed TTTS

• IUGR (typically the “donor”)

• Chorion-amnion separation

• Septostomy with tangled cords

Complications of TTTS

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Monochorionic TwinsTwin Anemia-Polycythemia Sequence

Monochorionic TwinsTwin Anemia-Polycythemia Sequence

Slaghekke et al. Lancet 2014;383:2144-51

Monochorionic TwinsTwin Anemia-Polycythemia Sequence

• Direct intravascular transfusion of anemic donor

• Direct intravascular transfusion of anemic donor w/ exchange transfusion of plethoric recipient

• Intraperitoneal transfusion of anemic donor

Genova et al. Fetal Diag Ther 2013;34:121-126

Monochorionic TwinsTwin Anemia-Polycythemia Sequence

Herway et al. Ultrasound Obstet Gynecol 2009;33:592-4

Monochorionic TwinsSurveillance After Laser for TTTS

• Ultrasounds weekly with Dopplers including MCA’s

Complications usually noted in first few weeks

• Delivery at 35 – 37 weeks

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