Twin Anemia-Polycythemia Sequence
Twin anemia-polycythemia sequence (TAPS) is a form of chronic inter-twin transfusion.
Monochorionic twin pregnancy complication
Diagnosis and staging
Different stages of TAPS are identified using the criteria as shown in the following tables.
Postnatal classification
| Postnatal stage | Intertwin hemoglobin difference (g/dL) |
|---|---|
| Stage 1 | >8.0 g/dL |
| Stage 2 | >11.0 g/dL |
| Stage 3 | >14.0 g/dL |
| Stage 4 | >17.0 g/dL |
| Stage 5 | >20.0 g/dL |
Treatment
The use of the so-called Solomon technique or dichorionization in fetoscopic laser therapy for TTTS is proven to be beneficial in preventing post-laser TAPS. With this technique, not only all anastomoses are coagulated but also a line is drawn between those in order to coagulate anastomoses that might not (yet) be visible during fetoscopy. It should be stressed that the success of such a technique is highly dependent on the specific situation. For example, when one of the fetusses obstructs the view on the vascular equator (the part of the placenta where the anastomoses need to be coagulated), complete dichorionization by the Solomon technique might not be possible.
Perinatal outcome
See also
- Vanishing twin
- Twin-to-twin transfusion syndrome