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Twin anemia-polycythemia sequence in two monochorionic twin pairs without oligo-polyhydramnios sequence
E Lopriore1, J M Middeldorp, D Oepkes
1Division of Neonatology, Department of Pediatrics, J6-S Leiden University Medical Center, Albinusdreef 2, 2300 RC Leiden, The Netherlands. e.lopriore@lumc.nl
Placenta
|March 7, 2006
Summary
Twin anemia-polycythemia sequence (TAPS) is an uncommon chronic inter-twin transfusion in monochorionic twins. It causes severe anemia and polycythemia without twin oligo-polyhydramnios sequence (TOPS).
Area of Science:
- Perinatology
- Maternal-Fetal Medicine
- Twin Gestation Research
Background:
- Monochorionic twins are at risk for inter-twin transfusion due to placental vascular anastomoses.
- Classical twin-to-twin transfusion syndrome (TTTS) involves oligo-polyhydramnios sequence (TOPS).
- An uncommon form of chronic inter-twin transfusion, twin anemia-polycythemia sequence (TAPS), is described.
Observation:
- Two cases of monochorionic twins with TAPS, born at 33 and 34 weeks gestation, were reviewed.
- Fetal ultrasound examinations showed no signs of TOPS.
- At birth, donor twins exhibited severe anemia, and recipient twins showed polycythemia.
Findings:
- High inter-twin reticulocyte count differences indicated chronic inter-twin blood transfusion.
- Placental injection studies revealed unidirectional, small (<1mm) arterio-venous anastomoses.
- TAPS resulted in severe neonatal hematological complications, requiring transfusions.
Implications:
- TAPS represents an uncommon inter-twin transfusion distinct from TTTS, characterized by the absence of TOPS.
- The condition is hypothesized to be mediated by minuscule, unidirectional placental anastomoses.
- Antenatal diagnosis is possible with Doppler studies, and postnatal confirmation via hemoglobin and reticulocyte counts.
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