Twin-twin transfusion syndrome

Twin to twin transfusion syndrome (TTTS) is a potential complication that can occur in a monochorionic twin (either MCDA or MCMA) pregnancy. 

This complication can occur in ~10% (range 15-25%) of monochorionic pregnancies giving an estimated prevalence of ~1:2000 of all pregnancies.

Marked abdominal distension has been described as a clinical feature.

TTTS results from an unbalanced arterio-venous (AV) communication in the placenta with increasing evidence implicating asymmetric anastomotic patterns in its aetiology.

The smaller twin with oligohydramnious which also called "stuck twin" that pumps away blood is termed the donor twin while the larger twin receiving extra blood is termed the recipient twin.

The extent of the syndrome can be staged according to severity. One method proposed by Quintero et al. is as 3:

  • stage I: visible bladder in donor twin with normal Dopplers
  • stage II: empty bladder in donor twin with normal Dopplers
  • stage III: empty bladder in donor twin with abnormal Dopplers
  • stage IV: hydrops fetalis in recipient twin
  • stage V: demise of any twin

General features that may suggest towards the diagnosis include:

Features that may noted individually in each twin include:

Possible predictors in first trimester ultrasound:

  • presence of monochorionicity
  • increased nuchal translucency and/or disparity in nuchal translucency between the twins
  • poor crown-rump length growth of one fetus
  • membrane folding at 10-13 weeks of gestation
  • velamentous cord insertion

TTTS generally carries a poor prognosis. Serial sonographic monitoring is often common practice. Laser coagulation of the chorionic plate has been trialled as a management option. Other possible interventions include:

General imaging differential considerations include:

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Article information

rID: 4788
System: Obstetrics
Section: Syndromes
Synonyms or Alternate Spellings:
  • Twin to twin transfusion syndrome
  • Stuck twin syndrome
  • Intrauterine parabiotic syndrome
  • TTTS
  • Twin to Twin transfusion syndrome (TTTS)
  • Feto-fetal transfusion syndrome

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Cases and figures

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    Case 1: probable stage I
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    Case 2: stage III
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