Background This study aimed to evaluate blood carboxyhemoglobin (COHb) levels as an indicator of hemolysis and as an early predictor of phototherapy requirement in newborns with blood type A or B born to mothers with blood type O. Methods In this prospective observational study, enrolled infants were divided into two groups: Group 1 comprised newborns with maternal blood type O and infant blood type A or B, while Group 2 consisted of newborns born to mothers without blood type O. Total serum bilirubin and carboxyhemoglobin levels were assessed from cord blood samples at birth and venous blood samples at 24 h of life and compared between groups. None of the infants required intravenous immunoglobulin therapy or blood transfusion. Results A total of 100 term infants were included. Mean carboxyhemoglobin levels in cord blood and at 24 h of life were significantly higher in Group 1 compared with Group 2 (0.55 vs 0.48, p = 0.04; 0.69 vs 0.36, p = 0.002, respectively). The onset of phototherapy occurred significantly earlier in Group 1 than in Group 2 (48 vs 90 h, p = 0.01). Conclusion Elevated carboxyhemoglobin levels were observed in newborns with ABO incompatibility, and higher levels were associated with an earlier requirement for phototherapy.
Akyuz et al. (Wed,) studied this question.