Twin anemia polycythemia sequence

Dr Bahman Rasuli and Radswiki et al.

Twin anemia polycythemia sequence (TAPS) is considered a variant of the twin to twin transfusion syndrome (TTTS).

TAPS may occur spontaneously in up to 5% of monochorionic twins and may also develop after incomplete laser treatment in twin-to-twin transfusion syndrome cases 2.

As with twin-to-twin transfusion syndrome, the underlying mechanism is thought to be abnormal placental vascular anastomoses, however, in TAPS the rate of transfusion is slow and therefore results in a gradual discordance of fetal hemoglobin, without the hormonal disbalance and subsequent liquor discordance seen in TTTS. One twin develops anemia and the other polycythemia.

One of the features suggesting the diagnosis is a discordance in fetal middle cerebral artery peak systolic velocity (MCA-PSV) measurements 4. In contrast to the classic twin-to-twin transfusion syndrome, there is no amniotic fluid discordance (i.e. no-twin oligo-polyhydramnios sequence (TOPS)) 5.

Article information

rID: 15453
Tag: cases, cases
Synonyms or Alternate Spellings:
  • Twin anaemia-polycythaemia sequence (TAPS)
  • Twin anaemia polycythaemia sequence (TAPS)
  • TAPS

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Cases and figures

  • Figure 1
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