How anaemia, thyroid disorders and periods form a vicious cycle for women

Heavy periods, iron deficiency and thyroid imbalance can quietly reinforce each other. Experts outline why women remain undiagnosed for years and what needs to change

Fatigue that refuses to go away, periods that feel heavier or more unpredictable each month, hair thinning, weight changes, and brain fog - for many women, these symptoms are treated as isolated problems or simply brushed aside as part of a busy life. However, doctors warn that these complaints are often deeply connected.

 

Anaemia, thyroid dysfunction, and menstrual disorders frequently coexist, quietly fuelling one another in what experts describe as a vicious cycle that undermines women’s reproductive and overall health.

 

Why these conditions are linked

 

According to Dr Aruna Thangapandy, Consultant – Obstetrics & Gynaecology at Rainbow Children’s Hospital, Marathahalli, the link between these conditions lies in the delicate balance of hormones, iron metabolism, and blood loss.

 

 

“In women, anaemia, thyroid dysfunction, and menstrual disorders are interwoven tightly and often together reinforce the whole situation, which is a rather vicious cycle,” she explains.

 

Iron deficiency, the most common cause of anaemia, affects far more than just energy levels. Iron is essential for oxygen delivery to tissues, including the thyroid gland and ovaries. When iron levels drop, thyroid hormone production and conversion also decline, increasing the risk of hypothyroidism.

 

At the same time, thyroid dysfunction interferes with the hypothalamic–pituitary–ovarian axis, which regulates menstrual cycles.

 

Hypothyroidism (too little thyroid hormone) is commonly associated with menorrhagia, or heavy menstrual bleeding. This excessive blood loss further depletes iron stores, worsening anaemia.

 

Over time, the cycle feeds itself - anaemia worsens thyroid function ->  thyroid imbalance disrupts menstruation -> heavy periods deepen iron deficiency.

 

Which problem shows up first?

 

In clinical practice, anaemia is usually the first condition to be detected, particularly among adolescent girls and women of reproductive age. Poor dietary iron intake combined with monthly blood loss makes this group especially vulnerable.

 

However, Dr Thangapandy points out that symptoms such as fatigue, dizziness, weakness, and hair fall are often normalised. “Anaemia is very often underdiagnosed, or if diagnosed, it is treated just superficially without unearthing the cause,” she says.

 

Thyroid dysfunction is typically identified much later, largely because its symptoms overlap with those of anaemia and menstrual problems. Unless thyroid tests are specifically ordered, many women remain undiagnosed for years.

 

Menstrual disorders are the least recognised of all, as irregular or heavy periods are often accepted as normal or managed temporarily without proper hormonal or metabolic evaluation.

 

Research and clinical experience suggest that many women seeking treatment for infertility or heavy periods are actually living with undetected anaemia or thyroid imbalance, prolonging symptoms and increasing long-term health risks.

 

How heavy, irregular periods worsen the problem

 

Heavy or irregular menstrual cycles play a central role in sustaining this vicious cycle. Prolonged bleeding leads to chronic iron loss every month, making it difficult for diet or supplements alone to replenish iron stores. As haemoglobin levels fall, oxygen delivery to tissues drops, including to the thyroid gland.

 

Iron deficiency directly impairs thyroid hormone synthesis and conversion, increasing the likelihood of hypothyroidism. In turn, altered thyroid hormone levels disrupt the balance of hormones oestrogen and progesterone, leading to irregular ovulation, unpredictable cycles, or heavier bleeding.

 

At the same time, anaemia itself affects ovarian function and metabolism, worsening hormonal imbalance. Together, heavy periods, iron deficiency, and thyroid dysfunction reinforce one another, gradually eroding women’s reproductive health and overall wellbeing.

 

Warning signs that demand attention

 

Dr Smrithi D Nayak, Consultant – Obstetrics & Gynaecology at Aster RV Hospital, Bangalore, stresses that these conditions are often missed because symptoms are subtle and treated in isolation.

 

“Women and clinicians should be alert when multiple subtle symptoms appear together, rather than in isolation,” she says.

 

Key warning signs include:

 

• Persistent fatigue despite iron supplementation
• Heavy, prolonged, or unpredictable menstrual cycles
• Hair thinning, dry skin, cold intolerance, or unexplained weight gain
• Shortness of breath, palpitations, or reduced exercise tolerance
• Mood changes, brain fog, or declining work productivity

 

Why current screening practices fall short

 

From a public health perspective, current screening practices remain inadequate, particularly for adolescents and working-age women in India.

 

Routine haemoglobin testing alone often misses early iron deficiency and subclinical thyroid dysfunction. Menstrual health, meanwhile, is rarely assessed in a structured or systematic way. Reluctance to speak openly about periods means warning signs are often ignored, allowing treatable conditions to quietly worsen.

 

As a result, women may continue to experience fatigue, hair loss, weight changes, and cycle disturbances despite iron therapy, because the underlying thyroid or hormonal contributor remains untreated.

 

Breaking the cycle: What experts recommend

 

Both experts emphasise the need for integrated care rather than fragmented, symptom-by-symptom treatment. Clinical strategies include:

 

• Combined screening for haemoglobin, ferritin, and thyroid function in women with menstrual complaints or unexplained fatigue
• Treating iron deficiency and thyroid dysfunction simultaneously, rather than sequentially
• Individualised menstrual management, including hormonal regulation where appropriate

 

Preventive and public health approaches are equally important:

• Nutrition strategies addressing iron, iodine, selenium, and adequate protein intake
• School- and workplace-based screening programmes
• Menstrual health education to encourage early reporting of symptoms
• Long-term follow-up to prevent relapse

 

“In India, early screening for anaemia alone is not enough,” Dr Nayak notes. Unless iron status, thyroid health, and menstrual patterns are addressed together, women remain trapped in a recurring cycle of poor health.

 

Early diagnosis, coordinated treatment, and awareness are key to breaking this vicious cycle and restoring long-term health and quality of life.

   

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This report is for informational purposes only and is not a substitute for professional medical advice.