A study aimed to extend a physiologically based method for determining serum ferritin (SF) concentration thresholds for iron deficiency (ID) in healthy pregnant women. Previous research has shown that in nonpregnant women, a decline in hemoglobin (Hb) and a rise in soluble transferrin receptor (sTfR1) concentrations can be used to identify the onset of ID.

The study’s results indicate that the SF threshold for ID is approximately 25 μg/L in the first trimester and around 20 μg/L in the second and third trimesters. These thresholds align with the physiological changes in hepcidin, the hormone that regulates iron mobilization, during pregnancy. The findings suggest that current WHO and CDC guidelines, which set the threshold for ID at ≤15 μg/L, may not adequately identify all pregnant women who are iron deficient, potentially leading to unrecognized and untreated ID. This can have significant health consequences for both the mother and child. The study calls for further research and validation of these physiologically based thresholds in diverse populations and emphasizes the need for updated guidelines to improve the management of ID in pregnancy.

Reference: Mei Z, Addo OY, Jefferds MED, Flores-Ayala RC, Brittenham GM. Physiologically based trimester-specific serum ferritin thresholds for iron deficiency in US pregnant women. Blood Adv. 2024 Jul 23;8(14):3745-3753. doi: 10.1182/bloodadvances.2024013460. PMID: 38781318; PMCID: PMC11296244.