BS ISO 45010 and menstrual leave: a guide for employers

What is menstrual leave?

Menstrual leave is dedicated time off, separate from ordinary sick leave, for people whose period pain or menstrual conditions genuinely prevent them working. A handful of countries have written it into law; Montenegro joined them in 2026 with an allowance of two paid days a month. The conditions attached are revealing: eligibility depends on a specialist diagnosis, renewed annually, with a certificate submitted to the employer each January. Set that against the reality that endometriosis — among the most common causes of disabling period pain — takes roughly eight years on average to diagnose, and the gap between an entitlement on paper and one a woman can actually reach becomes clear.

Does menstrual leave get used where it exists?

Uptake is the most honest measure available, and it is remarkably low everywhere the policy exists. Japan wrote menstrual leave into law in 1947; surveyed nearly eighty years later, fewer than 2% of women reported having used it, while almost half said there had been times they needed it and stayed silent. Spain, two years into its own law, sees it used by fewer than five women a day across a workforce of 21 million. The pattern is consistent: a right that exists on paper is not the same as a right a woman feels safe exercising.

What do these laws achieve?

• Formal recognition, in law, that menstrual pain and diagnosed conditions can require time away from work and appropriate support.
• Permission for the subject to exist at work at all: a legal precedent makes the conversation harder to dismiss.
• Momentum. Each country that legislates lowers the taboo a little for every other.

And what are the risks?

• The visibility cost. Claiming the leave identifies you as someone who takes extra time off, and in plenty of workplaces — though not all — that still quietly shapes who gets stretched, promoted and trusted.
• Bias upstream of the policy: at hiring, and in assumptions about capability, that no leave entitlement can reach.
• Perceived unfairness. An allowance that can total weeks a year for some colleagues and none for others can pull a team apart rather than together.
• A stigma rebound: a special category of absence can end up marking the topic out as other — the opposite of what it set out to do.

How does BS ISO 45010 inform workplace support?

BS ISO 45010 (ISO 45010:2026) is the current international guidance on menstruation and menopause in the workplace, published 7 September 2026. It provides a wider framework for reviewing workplace policies, practices and adjustments.^[1] Employers considering leave can use that wider lens to discuss privacy, access to support, facilities and flexible work design.

The UK predecessor, BS 30416:2023, was withdrawn and formally superseded by BS ISO 45010 on 7 September 2026. Our guide to BS ISO 45010 explains the current guidance and what changed. It does not create a legal entitlement to leave or provide organisational certification.

So should your workplace introduce menstrual leave?

Our honest answer: weigh it carefully inside your own culture, rather than adopting or rejecting it on the strength of a headline. Everything in the uptake evidence points the same way — what transforms a woman's working month is rarely the entitlement itself, but a manager who understands, flexibility that is real rather than nominal, and being measured on what she delivers instead of when and where she delivers it. Build those foundations first and a workplace may find it already has what menstrual leave promises, without the visibility cost that keeps the entitlement unused. Legislate — or write the policy — without them, and the risk is a benefit that sits untouched on the books while the silence continues.

If you are weighing this up for your organisation, start with where you actually stand — our free 3-minute workplace scorecard is informed by BS ISO 45010 — and read our guides to menstrual health in the workplace and cycle-aware working. We are always happy to talk it through.

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