Maternal Anemia and Erythrocytosis Linked to Severe Neonatal Morbidity and Mortality
A study of over 1.1 million births found a U-shaped relationship between early pregnancy hemoglobin levels and severe neonatal morbidity and mortality, with both anemia and erythrocytosis increasing risk.
Maternal anemia and relative erythrocytosis in early pregnancy are associated with severe neonatal morbidity and mortality (SNM-M) in a high-income setting, according to a population-based, retrospective cohort study published in the Annals of Internal Medicine.
The study examined early pregnancy hemoglobin concentration and its association with SNM-M among women aged 18 to 50 years with a singleton birth between 2007 and 2023. A total of 1,100,341 births were included, with hemoglobin measured at two to 12 weeks of gestation.
Researchers identified a U-shaped relationship between early pregnancy hemoglobin concentration and SNM-M. Compared with a hemoglobin value of 125 g/L — which corresponded to an SNM-M rate of 6.7 percent — the adjusted relative risk for SNM-M was 1.08 at a hemoglobin concentration of 105 g/L and 1.17 at 90 g/L. On the higher end, the adjusted relative risk for SNM-M was 1.05 at a hemoglobin concentration of 135 g/L and 1.20 at 150 g/L.
"In conclusion, these findings confirm the association between maternal anemia in pregnancy and unfavorable perinatal outcomes within a high-resource setting," the authors wrote. They noted that future prospective studies and clinical trials should evaluate neonatal outcomes across varying levels of hemoglobin correction and the optimal thresholds for initiating iron therapy.