Maternal hemoglobin decline following 'uneventful' cesarean delivery

Objective: To assess hemoglobin (Hb) decline following elective and non-elective uneventful cesarean section (CS). Methods: A retrospective cohort study of all women with singleton pregnancy who underwent uneventful CS defined as clinical estimation of intra-operative bleeding <1000 ml. Hemoglobin decline (pre- and post-CS levels difference) of women with non-elective CS (during labor/delivery process) were compared to those who underwent elective CS (no labor). Cases complicated by placenta previa/abruption were excluded. Results: Overall 2767 women underwent uneventful CS, of them, 954 (34.5%) were non-elective and 1813 (65.5%) were elective. Hemoglobin decline was higher in the non-elective group (1.5 +/- 1.3 versus 1.0 +/- 1.2 g/dL, p<0.001). This was also observed in the nulliparous patients as well as in those with previous single CS subgroups. The rate of Hb decline >= 3 g/dL and the rate of post-CS Hb<7 g/dL were higher in the non-elective group (8.9% versus 3.1%, p<0.001 and 2.3% versus 0.4%, p = 0.001, respectively). On multivariable analysis, non-elective CS was found to be significantly associated with Hb decline of >= 3 g/dl after surgery (aOR = 2.10, 95% CI 1.36-3.23, p = 0.001) and need for blood products transfusion (aOR = 2.24, 95% CI 1.04-4.83, p = 0.03). Conclusion: Non-elective CS was associated with an increased risk of Hb decline and blood product transfusion even in an apparent uneventful operation.