Objective: The purpose of this study was to assess fetal tissue venous oxygenation (StO2%) in utero during laser therapy for twin-twin transfusion syndrome via visible light spectroscopy (VLS).
Study design: StO2% was measured in 10 donor and recipient twins at the level of the skin and placenta before and after laser therapy (SLPCV).
Results: Pre-SLPCV skin StO2% was significantly lower in the donor than in the recipient twin (21.6 +/- 6.2 vs 31.2 +/- 8.6, respectively; P = .01), but the difference disappeared after SLPCV. Placental surface StO2% measurements in 5 patients showed a significant increase in StO2% in the territory of the recipient (P = .04). Preoperative linear streaming as evidence of nonadmixing deoxygenated and oxygenated blood disappeared after SLPCV.
Conclusion: In utero StO2% measurement is possible with VLS. Donor twins can have significantly less StO2% than recipient twins, but this is corrected after SLPCV. Further studies are warranted to determine the value of in utero VLS oximetry.