Iron Deficiency without Anemia: A Common Yet Under-Recognized Diagnosis in Young Women with Heavy Menstrual Bleeding.

Study Objective: To assess the proportion of iron deficiency that is not detected with a screening hemoglobin or complete blood count (CBC) alone in young women with heavy menstrual bleeding.

Design: Retrospective review of electronic medical records.

Setting: Nationwide Children's Hospital in Columbus, Ohio.

Participants, Interventions, And Main Outcome Measures: One hundred fourteen young women aged 9-19 years consecutively referred to a young women's hematology clinic with a complaint of heavy menstrual bleeding.

Results: Fifty-eight (50.9%) of all patients had ferritin <20 ng/mL indicating iron deficiency. Of the 58 patients with iron deficiency, only 24 (41.4%) were anemic and 25 (46.3%) were microcytic. The sensitivity of hemoglobin alone and CBC alone for identifying women with ferritin <20 ng/mL was 41.4% (95% confidence interval [CI], 28.7-54.1) and 46.3% (95% CI, 33.0-59.6), respectively. Both tests had reasonable specificity at 91.1% (95% CI, 83.6-98.5) for hemoglobin and 83.9% for CBC (95% CI, 74.3-93.6). Patients had significantly higher odds of having iron deficiency if they were overweight or obese (odds ratio, 2.81; 95% CI, 1.25-6.29) compared with patients with normal body mass index. Age at presentation for heavy menstrual bleeding, presence of an underlying bleeding disorder, and median household income were not significantly associated with iron deficiency.

Conclusion: In adolescents with heavy menstrual bleeding, fewer than half of iron deficiency cases are detected when screening is performed with hemoglobin or blood count alone. Measuring ferritin levels in at-risk patients might allow for earlier implementation of iron therapy and improvement in symptoms.