Ferritin Level Decreases During Menstruation
Ferritin levels typically decrease by approximately 10-27 ng/mL during menstruation, with the exact amount varying based on individual menstrual blood loss volume. 1, 2
Factors Affecting Ferritin Reduction During Menstruation
- The average menstrual blood loss is approximately 59.3 ± 25.1 g (range: 24-110 g), which directly correlates with the degree of ferritin reduction 1
- Menstrual blood loss is negatively correlated with serum ferritin levels - greater blood loss leads to more significant decreases in ferritin 1
- The duration of menstrual bleeding significantly impacts ferritin levels, with longer periods associated with lower ferritin levels 2
Baseline Ferritin Levels in Menstruating Women
- The average serum ferritin concentration in premenopausal women is approximately 42 μg/L (compared to 80 μg/L in postmenopausal women) 2
- Among premenopausal women:
- 12.1% have depleted iron stores (ferritin ≤20 μg/L)
- 35.6% have small iron stores (ferritin 21-40 μg/L) 2
- The average ferritin level in female undergraduate students is 25.13 ± 14.33 ng/mL, with 22.58% showing iron reduction (ferritin <12 ng/mL) 1
Impact of Contraceptive Methods on Menstrual Blood Loss and Ferritin
- Women using hormonal contraceptives have shorter menstrual bleeding duration and higher median ferritin levels (62 μg/L) 2
- Women not using pills or IUDs have moderate bleeding duration with median ferritin of 42 μg/L 2
- IUD users experience longer bleeding duration with lower median ferritin levels (36 μg/L) 2
- Levonorgestrel-releasing IUDs are associated with reduced risk of iron deficiency (OR = 0.06) 3
Clinical Implications
- Menstrual blood loss accounts for approximately 8% of the explained variance in hemoglobin levels in premenopausal women 3
- Heavy menstrual bleeding (PBAC ≥150) is associated with 3.56 times higher risk of anemia 3
- After iron supplementation, serum ferritin can increase from an average of 24 to 41 μg/L within one month, but will decrease again after supplementation ends 4
- No clinical anemia does not necessarily indicate good iron nutritional status - serum ferritin is a more sensitive indicator 1
Monitoring Considerations
- Serum ferritin is the most specific indicator available for depleted iron stores 5
- In women of childbearing age, ferritin ≤15 μg/L has 75% sensitivity and 98% specificity for iron deficiency 5
- When monitoring ferritin levels in menstruating women, timing of measurement relative to menstrual cycle should be considered due to cyclical variations 1, 2
- For accurate assessment of iron stores, measurements should ideally be taken at the same phase of the menstrual cycle when comparing values over time 2