From the Guidelines
Hypoferritinemia in pregnancy is defined as a serum ferritin concentration of less than or equal to 15 ug/L.
Key Points
- This definition is based on the sensitivity and specificity of low serum ferritin concentration for iron deficiency, with a sensitivity of 75% and specificity of 98% when set at less than or equal to 15 ug/L 1.
- A serum ferritin concentration of less than 12 ug/L has a sensitivity of 61% and specificity of 100% for iron deficiency 1.
- Maternal iron deficiency anemia (IDA) during pregnancy has been associated with adverse neonatal outcomes, including preterm birth, low birth weight, and neurocognitive abnormalities 1.
- Screening for maternal iron status early in pregnancy, including measurement of hemoglobin (Hb) and ferritin concentrations, is crucial to identify iron-deficient and anemic women who would benefit from iron supplementation during pregnancy 1.
- The World Health Organization recommends a cut-off value of 15 μg/L for serum ferritin to define iron deficiency in pregnant women, which is consistent with the findings of the study 1 and is also supported by more recent research 1.
From the Research
Definition of Hypoferritinemia in Pregnancy
Hypoferritinemia in pregnancy refers to a condition where the serum ferritin levels are below a certain threshold, indicating low iron stores. According to various studies, the thresholds for serum ferritin levels in pregnancy vary, but common values include:
- <12 ng/mL and <15 ng/mL 2
- <15 μg/L for the first trimester, with no recommendations for the second and third trimesters by the World Health Organization 3
- <25.8 μg/L for the first trimester, <18.3 μg/L for the second trimester, and <19.0 μg/L for the third trimester 3
- <30 μg/L 4
- <20 µg/L 5, 6
Diagnosis and Implications
Hypoferritinemia in pregnancy can be diagnosed by measuring serum ferritin levels, which is a better indicator of iron status than serum iron and hemoglobin levels 5. Low iron stores can occur with increasing frequency as gestation advances, and all patients should be given iron supplements in pregnancy, irrespective of social class or parity 5. The condition can lead to iron-deficiency anemia, which can have adverse effects on pregnancy outcomes, such as shorter gestation and lower birth weight 6.
Key Findings
- Serum ferritin levels decrease during pregnancy, with geometric mean levels higher during the first trimester and lower during the second and third trimesters 3
- Using a serum ferritin threshold of <15 μg/L may underestimate the true prevalence of iron deficiency throughout pregnancy 3
- Iron deficiency occurs frequently in pregnancy and can be diagnosed by serum ferritin-level measurement, with a threshold value of <30 μg/L 4
- Screening for iron-deficiency anemia is recommended in every pregnant woman, with serum ferritin-level screening in the first trimester and regular hemoglobin checks at least once per trimester 4