Many women have painful periods, but only a handful of countries, most of them in Asia, allow them to take time off work to recover.
Change is in the air, however.
On Thursday, Dec. 15, Spain's officials began debating legislation that would make it the first European country to offer menstrual leave.
In several other countries, companies have started offering period leave without being legally required to do so.
Here is a summary of the situation worldwide.
Spain's left-wing government in May unveiled a bill giving women unlimited paid leave for period pain, provided they have a doctor's note.
Equality Minister Irene Montero vowed: "No more going to work with pain, no more taking pills before arriving at work and having to hide the fact we're in pain that makes us unable to work."
The proposal drew criticism from Spanish unions, who warn that, far from liberating women, menstrual leave could prompt employers to prioritize men when hiring.
Indonesia passed a law in 2003 giving women the right to two days of paid menstrual leave per month, without giving prior notice.
But the provision is in practice discretionary.
Many employers allow only one day a month, while others give no menstrual leave at all, either because they are unaware of the law or choose to disregard it.
In Japan, a law dating as far back as 1947 states that companies must agree to give women menstrual leave if they request it, for as long as they need it.
It does not, however, require them to pay women during menstrual leave, but around 30 percent of Japanese companies offer full or partial pay, according to a 2020 labor ministry survey.
Not many women take advantage of the law, however. The survey of around 6,000 companies found that just 0.9% of eligible workers had taken menstrual leave.
In South Korea, women are entitled to one day of unpaid menstrual leave per month. Employers who refuse face fines of up to 5 million won (over P212,000).
A 2018 survey showed greater take-up than in Japan, with a little over 19% of women taking time off.
In Taiwan, the Act of Gender Equality in Employment gives women three days of menstrual leave per year, which are not deducted from the statutory 30 days of regular sick leave.
Women can only take one day in any given month.
Like sick leave, workers on menstrual leave receive only 50% of their salary.
Zambia passed a law in 2015 allowing women to take a day off work during their period, without giving notice or supplying a doctor's note.
While the measure is generally accepted and supported, not all employers willingly comply with the law on what is discreetly referred to as "Mother's Day."
But, encouraged by trade unions, women are starting to exercise their right, communications expert and women's rights advocate Ruth Kanyanga Kamwi told AFP.
Some companies have not waited to be compelled by law to offer women menstrual leave.
They include Australian pension fund Future Super, Indian food delivery startup Zomato, and French furniture firm Louis which give respectively six, 10, and 12 extra days.
On its website, Los Angeles-based astrology company Chani also offers "unlimited menstrual leave for people with uteruses." (AFP)