Heavy menstrual bleeding triples risk of iron deficiency in teenage girls, Study finds - Video

Feeling constantly tired or unfocused might have more to do with your menstrual cycle than you think. A new study from Lund University in Sweden, published in PLOS One, has found that more than half of teenage girls experience heavy menstrual bleeding, and four in ten have iron deficiency as a result. The research also shows that a simple questionnaire could help schools and clinics identify those most at risk—offering a fast, inexpensive way to prevent anemia among young women.

Iron plays a critical role in energy, concentration, and oxygen transport. Yet, many teenagers fail to recognize the link between menstrual health, diet, and fatigue. To explore this, researchers studied 394 girls aged 15 and older from two upper secondary schools. Each participant completed questions about their menstrual experiences and dietary habits, followed by blood tests measuring hemoglobin (Hb) and ferritin, a marker of iron stores.

The results were striking. Girls with heavy menstrual bleeding were three times more likely to have low iron levels than those with normal cycles. When combined with a meat restricted or vegetarian diet, the risk increased dramatically—up to thirteen fold higher than their peers. Among those reporting heavy bleeding, 52% had iron deficiency compared with 26% among girls with normal bleeding. Similarly, 62% of participants who avoided red meat had low iron stores, and in the group with both risk factors—heavy bleeding and no red meat intake—iron deficiency soared to 71%.

To address early detection, the team tested a Spanish screening tool called the SAMANTA questionnaire, designed to assess the severity of menstrual bleeding. For the first time, it was used among teenagers, and it successfully identified girls most likely to have low iron. Researchers say this tool could be easily integrated into school health programs or youth clinics to guide early interventions such as dietary counseling or iron supplementation.

Lead researcher Dr. Moa Wolff stressed that many young people underestimate their symptoms or rely solely on personal comparisons. “We see many girls who are tired and distracted, but linking that to menstruation isn't obvious,” she said. By recognizing heavy bleeding as more than an inconvenience, the study urges schools, families, and clinicians to take menstrual health seriously—because treating iron deficiency early can improve wellbeing now and protect women’s health later in life.

REFERENCE: Söderman, L., et al. (2025). Exploring the effect of menstrual loss and dietary habits on iron deficiency in teenagers: A cross-sectional study. PLOS One. DOI: 10.1371/journal.pone.0336688. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0336688