Temporal changes in transcutaneous hemoglobin levels and their influencing factors in postpartum women: a longitudinal study

This study aimed to clarify the temporal changes in transcutaneous hemoglobin levels up to 1 month postpartum and the influencing factors in postpartum women using a noninvasive transcutaneous hemoglobin measuring device. The study participants were pregnant women recruited at an outpatient clinic. We collected information on their dietary history using a concise self-administered questionnaire and an agreement document when they were hospitalized for delivery. Transcutaneous hemoglobin levels of the mothers were measured using Pronto (Masimo) at 1 day, 4 days, 2 weeks, and 1 month postpartum. We included 135 mothers (mean age, 31.7 years) who delivered at full term. The mean transcutaneous hemoglobin levels decreased slightly from day 1 (11.9 +/- 1.6 g/dL) to day 4 postpartum (11.8 +/- 1.7 g/dL), followed by a significant increase from day 4 to 2 weeks postpartum (13.8 +/- 1.0 g/dL; p < 0.01), and no change from 2 weeks to 1 month postpartum (13.8 +/- 0.9 g/dL). Iron intake in the third trimester of pregnancy affected transcutaneous hemoglobin levels from day 4 postpartum to recovery by 2 weeks postpartum. The rapid increase in hemoglobin levels from day 4 to 2 weeks postpartum was a novel finding. Evaluation of hemoglobin levels in women at 2 weeks postpartum is important for postpartum recovery. Furthermore, health guidance regarding iron intake in the third trimester of pregnancy has been suggested to be effective in restoring postpartum hemoglobin levels.