{
  "slug": "iron-deficiency-reproductive-age-women",
  "question": "What are the odds a woman of reproductive age is iron deficient?",
  "quick_answer": "About 25.5% of US women aged 12-49 — roughly 1 in 4 — are iron deficient at any given time (NHANES 2015-2016). Most people guess a 5-10% chance and treat it as rare, but it is the predictable result of monthly blood loss meeting a diet low in absorbable iron.\n",
  "category": "food",
  "tags": [
    "food"
  ],
  "no_reliable_estimate": false,
  "perceived": {
    "description": "Iron deficiency reads to most people as a Victorian complaint -- pale heroines fainting on chaise longues -- or, at most, something a pregnant woman is told to watch. The modern intuition is that a normal diet covers it and that \"tired all the time\" is about sleep or stress, not blood chemistry. Few menstruating women would guess that roughly one in four of them is running low on iron at any given moment, and that the depletion is a direct arithmetic consequence of monthly blood loss rather than a rare disorder.\n",
    "rough_estimate": "~5-10% chance for a typical woman",
    "kind": "intuition"
  },
  "native": {
    "display": "~25.5% of US females aged 12-49 had iron deficiency (inflammation-adjusted serum ferritin <15 µg/L, NHANES 2015-2016)",
    "numerator": 25.5,
    "denominator": 100,
    "unit": "cross-sectional prevalence of iron deficiency among reproductive-age US females",
    "population": "US females aged 12-49 (NHANES 2015-2016, CDC/NCHS)"
  },
  "normalized": {
    "lifetime_us_adult": 0.255,
    "display": "~1 in 4 US women aged 12-49 is iron deficient (25.5% point prevalence, NHANES 2015-2016)",
    "log_value": -0.59,
    "assumptions": "The headline is the cited figure itself, un-inflated: Healthy People 2030 sets the national baseline at 25.5% of females aged 12-49 with iron deficiency in 2015-2016, defined as inflammation-adjusted serum ferritin <15 µg/L (CRP-corrected via the BRINDA method). That is a cross-sectional snapshot — at any single blood draw, roughly a quarter of reproductive-age women are below the threshold. Because iron deficiency in this group is driven by recurring menstrual blood loss and the demands of pregnancy, it recurs and remits across a ~35-year reproductive span, so the cumulative probability that a given woman is deficient at SOME point is plausibly higher than the 25.5% snapshot — but that cumulative figure is not separately measured, so it is left as the upper end of the uncertainty band rather than asserted as the headline. The wide band also spans the definitional spread: a stricter 2-of-3-biomarker definition puts non-pregnant prevalence near 9.8% (NHANES 1999-2006), while a higher ferritin cutoff (~25 µg/L) would push it above the headline. The scope is a reproductive-age-woman subgroup, not a general US-adult lifetime — for men and postmenopausal women the figure is a small fraction of this.\n",
    "uncertainty": {
      "low": 0.1,
      "high": 0.4
    },
    "scope": "subgroup_lifetime"
  },
  "sources": [
    {
      "url": "https://odphp.health.gov/healthypeople/objectives-and-data/browse-objectives/nutrition-and-healthy-eating/reduce-iron-deficiency-females-aged-12-49-years-nws-17/data-methodology",
      "title": "Reduce iron deficiency in females aged 12 to 49 years — NWS-17, Data Methodology",
      "publisher": "Office of Disease Prevention and Health Promotion (Healthy People 2030), U.S. HHS",
      "source_type": "govt_report",
      "statistic": "Baseline: 25.5% of females aged 12-49 had iron deficiency in 2015-2016; national target 21.7%. Source: NHANES, CDC/NCHS.",
      "excerpt": "\"Females 12 to 49 years are defined as having iron deficiency if they have a measurement of inflammation-adjusted serum ferritin less than 15µg/L.\"\n",
      "source_date": "2020-08-18",
      "source_accessed": "2026-07-18",
      "archive_url": "http://web.archive.org/web/20260511054220/https://odphp.health.gov/healthypeople/objectives-and-data/browse-objectives/nutrition-and-healthy-eating/reduce-iron-deficiency-females-aged-12-49-years-nws-17/data-methodology",
      "calculation_notes": "Healthy People 2030 objective NWS-17. Baseline 25.5% in 2015-2016, target 21.7%. Underlying data: National Health and Nutrition Examination Survey (NHANES), CDC/NCHS. The deficiency threshold is inflammation-adjusted serum ferritin <15 µg/L, adjusted for C-reactive protein using the BRINDA regression approach (a change from the Healthy People 2020 total-body-iron indicator). The 25.5% figure feeds both the native prevalence and the normalized headline directly (0.255), un-inflated; the cumulative-over-reproductive-years effect is carried in the upper uncertainty bound rather than the point estimate.\n"
    },
    {
      "url": "https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/",
      "title": "Iron — Health Professional Fact Sheet",
      "publisher": "NIH Office of Dietary Supplements",
      "source_type": "govt_report",
      "statistic": "Pregnant women, women with heavy menstrual bleeding, and frequent blood donors are named among the groups more likely to have inadequate iron intakes / higher risk of iron deficiency.",
      "excerpt": "\"Certain groups of people are more likely than others to have inadequate iron intakes, including pregnant women, infants and young children, women with heavy menstrual bleeding, and frequent blood donors. People with certain conditions, such as cancer, gastrointestinal disorders, and heart failure, may also have inadequate iron intakes.\"\n",
      "source_date": "2025-09-04",
      "source_accessed": "2026-07-18",
      "archive_url": "http://web.archive.org/web/20260725194357/https://ods.od.nih.gov/factsheets/Iron-HealthProfessional/",
      "calculation_notes": "The NIH ODS fact sheet grounds the risk-group breakdown that feeds the personal_factor_multipliers (heavy menstrual bleeding, pregnancy, blood donation, vegetarian diet). It also supplies the measurement caveat: hemoglobin and hematocrit are insensitive screens, and serum ferritin — the marker used by Healthy People 2030 — is confounded by inflammation, which is why the CDC uses CRP adjustment. It does not itself state the 25.5% headline figure; that comes from the Healthy People 2030 / NHANES source above.\n",
      "independence_note": "NIH ODS is editorially independent of the ODPHP Healthy People objective; both draw on NHANES but are separately authored government references."
    },
    {
      "url": "https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0112216",
      "title": "Iron Status and Reproduction in US Women: National Health and Nutrition Examination Survey, 1999-2006",
      "publisher": "PLOS ONE (Mei, Cogswell, et al.)",
      "source_type": "peer_reviewed",
      "statistic": "Iron deficiency 9.8% in non-pregnant women vs 25.4% in pregnant women (NHANES 1999-2006), by a 2-of-3 biomarker definition.",
      "excerpt": "\"rates of iron deficiency were 9.8% in non-pregnant women and 25.4% in pregnant women.\"\n",
      "source_date": "2014-11-13",
      "source_accessed": "2026-07-18",
      "archive_url": "http://web.archive.org/web/20250430115816/https://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0112216",
      "calculation_notes": "NHANES 1999-2006. Iron deficiency defined as two of three of hemoglobin, serum ferritin (<12 ng/mL), and transferrin saturation (<16%) below cutoff — a stricter, older definition than the single-ferritin<15 threshold used by Healthy People 2030, which is why its non-pregnant figure (9.8%) is lower than the 25.5% headline. The pregnant-vs-non-pregnant contrast (25.4% vs 9.8%, a ~2.6x ratio) grounds the pregnancy multiplier and the cumulative-lifetime adjustment: even by the conservative definition, pregnancy alone lifts point prevalence to a quarter.\n",
      "independence_note": "Peer-reviewed NHANES analysis, independent of the government fact sheets though built on overlapping survey cycles."
    }
  ],
  "comparison_anchors": [
    {
      "label": "Type 2 diabetes (lifetime, US adult)",
      "lifetime_us_adult": 0.33
    },
    {
      "label": "Depression (lifetime, US adult)",
      "lifetime_us_adult": 0.2
    },
    {
      "label": "Vitamin D deficiency without supplements (lifetime)",
      "lifetime_us_adult": 0.35
    }
  ],
  "personal_factor_multipliers": [
    {
      "factor": "pregnancy",
      "multiplier": 2.6,
      "notes": "NHANES 1999-2006 (cited source): iron deficiency 25.4% in pregnant vs 9.8% in non-pregnant women (~2.6x). Expanded blood volume and fetal demand raise requirements to ~27 mg/day, which diet alone rarely meets — hence routine antenatal screening and supplementation guidance."
    },
    {
      "factor": "heavy menstrual bleeding",
      "multiplier": 2.5,
      "notes": "Directional estimate — magnitude not separately quantified in the cited ledger. NIH ODS names women with heavy menstrual bleeding among the highest-risk groups; menorrhagia (loss above ~80 mL per cycle) routinely outpaces dietary iron replacement, so it is the dominant driver of deficiency in this population. The ~2.5x value is a conservative directional figure grounded in that mechanism, not a cited relative risk."
    },
    {
      "factor": "vegetarian or vegan diet",
      "multiplier": 1.8,
      "notes": "Directional estimate. Non-heme plant iron is absorbed at roughly a third the rate of heme iron; the Institute of Medicine sets recommended iron intakes ~1.8x higher for vegetarians on that basis, which anchors this factor. Grounded in the absorption mechanism rather than a cited prevalence ratio."
    },
    {
      "factor": "frequent blood donor",
      "multiplier": 2,
      "notes": "Directional estimate. NIH ODS lists frequent blood donors among at-risk groups; each whole-blood donation removes ~200-250 mg of iron, enough to deplete stores faster than diet replaces them. The ~2x value is a conservative directional figure grounded in that iron-loss mechanism, not a cited relative risk."
    },
    {
      "factor": "postmenopausal or male (no menstrual loss)",
      "multiplier": 0.2,
      "notes": "Directional protective estimate. Without recurring menstrual loss, iron deficiency in men and postmenopausal women falls to low single-digit percentages (a small fraction of the reproductive-age-female baseline), and new deficiency in these groups is a flag to investigate gastrointestinal blood loss rather than diet."
    }
  ],
  "short_label": "Iron gap (women)",
  "myth_framing": "underrated",
  "outcome_severity": "moderate_harm",
  "exposure_pattern": "recurring",
  "outcome_type": "chronic_illness",
  "valence": "negative",
  "caveats": "This entry is scoped to females aged 12-49 — the population the deficiency burden actually falls on — not to a general US adult, for whom the figure would be a small fraction of this. \"Iron deficiency\" also depends heavily on where the ferritin line is drawn. Healthy People 2030 uses inflammation-adjusted ferritin <15 µg/L; some recent work argues the physiologically justified threshold for non-pregnant women is closer to ~25 µg/L, which would push prevalence higher still, while older WHO-style 2-of-3 definitions yield the lower ~10% non-pregnant figure. Iron deficiency is also a stage before iron-deficiency anemia: most deficient women are not yet anemic, and the symptom picture (fatigue, poor concentration, cold intolerance) overlaps with much else, so the condition is routinely missed. Ferritin is an acute-phase reactant that rises with inflammation, which is why the CDC applies CRP adjustment; an unadjusted ferritin can mask deficiency in someone with concurrent infection or obesity.\n",
  "quality_score": {
    "d1": 5,
    "d2": 5,
    "d3": 4,
    "d4": 5,
    "d5": 5,
    "d6": 5,
    "d7": 5,
    "d8": 5,
    "avg": 4.875,
    "scored_by": "claude-code-8d",
    "scored_at": "2026-07-18",
    "methodology_version": "1.0"
  },
  "reviewer": "8d-eval-2026-07-18",
  "last_reviewed": "2026-07-18",
  "reviewed": true,
  "generated_at": "2026-07-18",
  "image": {
    "alt": "A stylized iron nail resting on a calendar page, muted red and grey flat vector illustration."
  },
  "attribution": "Likelier — https://likelier.app",
  "license": "https://creativecommons.org/licenses/by-sa/4.0/",
  "support": "https://buymeacoffee.com/kgluszczyk?via=likelier&utm_content=api-fear-single",
  "canonical_url": "https://likelier.app/iron-deficiency-reproductive-age-women"
}