The relationship between maternal anemia and umbilical cord oxygen content at delivery

Abstract Objective This study examined the relationship between maternal anemia and fetal oxygenation status at delivery as measured by umbilical cord pO2. Methods This is a secondary analysis of a prospective cohort study of singleton term deliveries with universal admission CBC and umbilical cord gases between 2010 and 2014. Maternal anemia was defined as hemoglobin ≤ 10 g/dl on admission. The primary outcomes were umbilical artery (UA) and vein (UV) pO2; secondary outcomes were acidemia (UA pH 90th percentile). Outcomes were compared between patients with and without anemia. Results Maternal anemia was associated with a significantly higher UA pO2 [median (IQR) 20 (16, 24) vs 19 (15, 24) mmHg, p=0.01] and UV pO2 [30 (25, 36) vs 29 (23, 34) mmHg, p Conclusion Umbilical cord O2 content is higher in anemic mothers. Maternal anemia may lead to adaptations in maternal, placental and fetal physiology allowing for easier unloading of O2 to the placenta and increased O2 transfer to the fetus.