Iron Deficiency in Perimenopause: Is It Your Hormones or Is Your Iron Low?

Fatigue. Brain fog. Poor concentration. Headaches. Low energy. Dizziness. Changes in sleep.

If you are in your 40s, it can be very easy to put all of these symptoms under one umbrella:

Perimenopause.

And yes, perimenopause can absolutely cause or contribute to many of them.

But there may be something else going on at the same time.

Iron deficiency.

Iron deficiency is one of the most prevalent nutrient deficiencies worldwide and disproportionately affects women who menstruate. Importantly, iron deficiency can occur without anemia, which means a woman may be experiencing symptoms associated with inadequate iron status without being told she is anemic.

For women entering perimenopause, this distinction becomes particularly important.

What are the symptoms of iron deficiency in women?

Iron deficiency can be associated with symptoms including fatigue, lethargy, dizziness, shortness of breath, headaches, difficulty concentrating, difficulty thinking clearly and restless legs.

Now compare that list with some of the complaints commonly heard during perimenopause.

“I have no energy.”

“I can't concentrate anymore.”

“My brain feels foggy.”

“I am exhausted.”

“I can't sleep properly.”

“I don't feel like myself.”

There is significant overlap.

This is why Dr. Nicole Roberts, Ontario Naturopathic Doctor, considers iron status when clinically appropriate rather than assuming every symptom appearing in a woman's 40s is automatically caused by changing hormones.

Sometimes hormones are contributing.

Sometimes iron deficiency is contributing.

Sometimes it is both.

Why can perimenopause increase the risk of iron deficiency?

Menstrual patterns can change significantly during the perimenopausal transition.

For some women, periods become irregular. For others, bleeding becomes considerably heavier or lasts longer.

Heavy menstrual bleeding means greater blood loss and therefore greater potential iron loss.

Over time, this can deplete iron stores.

And the effects can extend far beyond your period itself.

Iron deficiency can affect energy, physical activity, cognition, work performance and overall quality of life. Women with heavy menstrual bleeding are also more likely to report taking days off work.

This is why heavy menstrual bleeding should not simply be dismissed as an inconvenient part of perimenopause.

Can I have low iron without anemia?

Yes.

This is one of the most important things women should understand about iron deficiency.

Iron deficiency and iron deficiency anemia are not interchangeable terms.

Your iron stores can become depleted before you progress to anemia. Symptoms and quality of life still matter during this stage.

This is also why assessing iron status may require more than looking at whether your hemoglobin has fallen outside of the laboratory reference range.

Is ferritin enough to diagnose iron deficiency?

Ferritin provides valuable information about stored iron, but Dr. Nicole Roberts does not view one lab marker in isolation.

A more complete clinical assessment may include a CBC, ferritin, iron and transferrin saturation, along with your symptoms, menstrual history, medications and overall health.

Inflammation can also complicate ferritin interpretation because ferritin can rise as part of an inflammatory response. This can potentially make iron status more difficult to interpret in some individuals.

The question should not simply be:

“Is my ferritin in range?”

We also need to ask:

What does the complete iron picture look like, what symptoms are occurring and why might this patient be losing or inadequately absorbing iron?

Why does treating heavy menstrual bleeding matter?

If menstrual blood loss is contributing to iron deficiency, we cannot only focus on replacing iron.

We also need to address the loss.

Research following women after intervention for heavy menstrual bleeding has demonstrated significant improvements in ferritin by approximately six months, with continued improvement afterward.

That is an important part of the clinical conversation.

Taking an iron supplement may help replace iron, but if you continue losing significant amounts of blood every month, we have not necessarily addressed the complete problem.

Is my fatigue from perimenopause or iron deficiency?

This is a common question, but it is not necessarily an either or situation.

A woman can be experiencing hormonal changes associated with perimenopause while simultaneously experiencing iron deficiency, sleep disruption, mood changes or another health concern.

This is why assessment matters.

We do not need to blame everything on hormones.

We also do not need to ignore hormones.

We need to look at the whole clinical picture.

Iron deficiency support for women in Ontario

Dr. Nicole Roberts is an Ontario Naturopathic Doctor who focuses her practice on women's health, including perimenopause, menopause, menstrual health, heavy menstrual bleeding and iron deficiency.

If you are experiencing persistent fatigue, brain fog, dizziness, headaches, restless legs or increasingly heavy periods, assessing your iron status may be an important part of understanding what is happening.

Perimenopause is a major hormonal transition.

It should not become an explanation that prevents us from investigating everything else.