Image copyright Churan Zheng

Several provinces in China now have laws in place to ensure women can take a day or two a month off work if they suffer from period pain. Events organiser Churan Zheng regularly takes menstrual leave, and says it is an essential option for every woman.

I suffer from severe period pain and every month post a picture on my social media accounts showing a woman tied to an invisible cross with arrows stuck into her stomach. It always get a lot of "likes" because it vividly visualises what many women suffer during their period.

I always get a heavy feeling and stomach cramps the night before my period starts. And when I wake up, the pain that accompanies the menstruation is so unbearable that I always imagine myself grabbing my intestines and tearing them out of my body, or cutting them out with a pair of scissors. I feel like vomiting.

Ever since I left university and started work I have taken painkillers almost every month but the drugs make me feel tired and sleepy. I need hot water bottles as well in order to battle the pain.

It's often difficult during these times for me to concentrate on my work, which makes me curse my gender.

Image copyright Churan Zheng Image caption Churan posts a picture every month on social media representing her period pain

Fortunately my company - Pride Planning, which works on female rights campaigns - offers female staff one paid day's leave every month. Employees do not need to get doctors' notes, or worry about their salary being deducted for dropping a day's work. In my case, as long as there is no business trip scheduled or important work to be finished, I normally take half a day or a day off. I just stay at home, sleeping after taking painkillers or doing some work in bed.

Some people think allowing women to take menstrual leave costs the business money, so there is a debate about whether it could discourage companies from hiring women. However, so far as I know, my company - where female employees are in the majority - doesn't suffer significant financial loss despite the fact that almost every woman takes menstrual leave every month, or every other month.

What is period pain?

Image copyright iStock

Most women experience pain as part of their menstrual monthly cycle.

It is usually experienced as abdominal cramps, which can spread to the back and thighs.

Period pain can be felt as a dull ache or painful spasms. Women can also experience nausea, diarrhoea and headaches.

The scientific term for period pain is dysmenorrhoea. Levels of the hormone prostaglandin, produced by cells in the lining of the womb, cause it to contract.

The higher that level, the more strongly and more often the womb contracts, causing the pain.

Some women can also experience pelvic pain, even when not on their period.

We tend to plan ahead before we take the leave, or try to catch up as soon as we can afterwards. Male colleagues don't seem to feel unfairly treated. In fact if anything our work environment has become more positive and friendly since the policy was introduced.

Other people might think that such policies are too protective of women and that they could result in female employees being seen as weak or lazy.

However, so far as I know, women who don't experience period pain normally don't take this kind of leave. Apart from anything else those who work for corporations that have a very competitive work culture do not want to be seen as "feeble" or "fussy". And as I say, in my company, people who do take the leave have to catch up with their work as soon as they get back, which brings added pressure.

Image copyright Reuters Image caption Churan was one of five feminists who were detained last year ahead of a planned protest against sexual harassment

It's strange that even today the idea of a day's paid leave for women can cause such heated debate and criticism. Profit and efficiency are worshipped above everything else.

Nature cannot free women from period pain, but isn't there something our society can do for women? I cannot stop thinking that if men had periods then menstrual leave might have been written into national constitutions from the very beginning.

What is 100 women?

BBC 100 Women names 100 influential and inspirational women around the world every year. We create documentaries, features and interviews about their lives, giving more space for stories that put women at the centre.

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Translation by Natalia Zuo