Restless legs in menopause: the link with your iron

Restless legs in menopause have more to do with your iron stores than with your hormones. A Cochrane review of ten studies with 428 participants found iron improved symptom scores more clearly than placebo (mean difference -3.78 on a 0 to 40 scale, 95% confidence interval -6.25 to -1.31), with evidence rated as moderate certainty (PMID 30609006).

That is notable, because most menopause symptoms have no usable blood value at all.

This one does. Which is why I find it striking that ferritin appears on no page about restless legs in menopause that I could find.

What exactly are restless legs?

An irresistible urge to move your legs, arriving at rest and disappearing as soon as you move. It is a clinical diagnosis with four fixed features, and those four are why it is recognisable without testing. It plays up in the evening and at night, and almost never in the morning.

Rest makes it worse, walking makes it better.

That last point is the distinguishing feature. With nearly every other cause of painful or tingling legs, moving does not help or makes it worse. Here, getting up and walking around is the relief, which is exactly why people pace their bedrooms at night (PMID 33880737).

Women get it roughly twice as often as men. It also becomes more common with age, and in perimenopause two further things arrive that matter independently: poorer sleep and, with heavy periods, a falling iron store.

Look at the second row. Improving on walking is the feature separating this from nearly everything else, and it is the first question your GP will ask.

What does iron have to do with it?

Iron is needed to make dopamine in your brain, and in this condition too little seems available there. That is the most accepted mechanism, and it explains why iron helps in studies of people whose stores are low.

Your brain runs short of iron before your blood does.

The Cochrane analysis looked wider than that one scale. Across eight studies with 370 participants iron stayed better than placebo, and quality of life improved across three studies with 128 participants. Sleep quality did not measurably improve, and side effects were no more common than with placebo (PMID 30609006).

Important alongside that: this concerns people whose iron stores were low. International treatment guidelines for iron in this condition exist, and they use ferritin thresholds higher than the lower limit a laboratory uses to rule out anaemia (PMID 29425576).

That is exactly where it goes wrong. A ferritin flagged as normal by the lab can still be on the low side for this complaint. Research into iron deficiency without anaemia in this condition shows that group exists and is not small (PMID 32425874).

Which blood values are useful here?

Ferritin above all, and not just your haemoglobin. Haemoglobin shows whether you already have anaemia. Ferritin shows how large your store still is, and that can have dropped considerably while your haemoglobin is still fine.

The difference between those two is the whole point here.

In perimenopause that difference is extra relevant. Periods can become heavier and less predictable in these years, and ongoing blood loss slowly drains your store before anything shows in your blood count. What a low ferritin with a normal haemoglobin means is in iron deficiency without anaemia, and the reference values in ferritin levels.

An iron status panel looks at ferritin and the rest of your iron handling, an anaemia panel adds your blood count. What your GP does with a result, and whether iron applies to you, is for your GP to judge. Taking iron on your own initiative is not a good idea here, because excess iron accumulates and that is not harmless.

So what does menopause have to do with it?

Indirectly a lot, directly little. There is no strong evidence that falling oestrogen causes this complaint. What there is: the two best-known amplifiers, poor sleep and a low iron store, both become more common in this phase.

Menopause sets the stage, iron plays the part.

That makes the conversation easier, not harder. You do not need to work out whether your hormones are behind it, because the question that pays off is a different one: how are my iron stores, and am I sleeping enough. What happens to your sleep in this phase is in poor sleep in menopause.

Take two women of 50 with restless legs in the evening. One has not had a period for two years and has a ferritin of 90. The other has had heavy, unpredictable periods since 47 and a ferritin of 18. Same complaint, and only in the second is there a clear thread to pull.

What do you take to your GP?

Three things. Whether walking relieves it, because that is the core question. What time of day it arrives. And how your periods have been over the past year, in heaviness and frequency.

Ask about your ferritin, not only your haemoglobin.

That is the most practical sentence in this whole piece. If blood is taken and only your blood count is measured, the question that pays off most here goes unanswered. Mention as well which medicines you take, because some can worsen this complaint.

For the wider picture of this phase, navigating perimenopause is the starting point.

References

1. Trotti LM, Becker LA. Iron for the treatment of restless legs syndrome. Cochrane Database Syst Rev. 2019;1:CD007834. PMID 30609006.
2. Allen RP, Picchietti DL, Auerbach M, et al. Evidence-based and consensus clinical practice guidelines for the iron treatment of restless legs syndrome/Willis-Ekbom disease in adults and children. Sleep Med. 2018;41:27-44. PMID 29425576.
3. Gossard TR, Trotti LM, Videnovic A, St Louis EK. Restless legs syndrome: contemporary diagnosis and treatment. Neurotherapeutics. 2021;18(1):140-155. PMID 33880737.
4. Zhu XY, Wu TT, Wang HM, et al. Correlates of nonanemic iron deficiency in restless legs syndrome. Front Neurol. 2020;11:298. PMID 32425874.
5. Dutch College of General Practitioners (NHG) guideline on sleep problems and sleep medication (M23). Available via richtlijnen.nhg.org.
6. Thuisarts. I have restless legs. Available via thuisarts.nl.
7. RIVM. Statistics on sleep problems in the Netherlands. Available via rivm.nl.

Every blood test result at Lunara includes a professional assessment by a BIG-registered doctor. For treatment decisions, discuss your results with your GP.