Placenta
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Review Meta Analysis Observational Study
Impact of cesarean section on placental transfusion and iron-related hematological indices in term neonates: a systematic review and meta-analysis.
Evidence suggests that cesarean section is likely associated with a reduced placental transfusion and poor hematological status in neonates. However, clinical studies have reported somewhat inconsistent results. We conducted a systematic review and meta-analysis to examine whether cesarean section affects placental transfusion and iron-related hematological indices. ⋯ Compared with neonates born vaginally, those born by cesarean section had a higher placental residual blood volume [weighted mean difference (WMD), 8.87 ml; 95% confidence interval (CI), 2.32 ml-15.43 ml]; a lower level of hematocrit (WMD, -2.91%; 95% CI, -4.16% to -1.65%), hemoglobin (WMD, -0.51 g/dL; 95% CI, -0.74 g/dL to -0.27 g/dL) and erythrocyte (WMD, -0.16 × 10(12)/L; 95% CI, -0.30 × 10(12)/L to -0.01 × 10(12)/L). Subgroup analysis showed that the WMD for hematocrit in neonate's peripheral blood (-6.94%; 95% CI, -9.15% to -4.73%) was substantially lower than that in cord blood (-1.75%; 95% CI, -2.82%, -0.68%) (P value for testing subgroup differences <0.001). In conclusion, cesarean section compared with vaginal delivery is associated with a reduced placental transfusion and poor iron-related hematologic indices in both cord and peripheral blood, indicating that neonates delivered by cesarean section might be more likely affected by iron-deficiency anemia in infancy.