A large number of girls in rural Kenya skip school at the time of their menstruation because they cannot afford to buy sanitary towels or tampons.
By Anne Mawathe
It's estimated some girls miss more than a month of school each year
The cost of these monthly necessities has been highlighted by women campaigners in Zimbabwe, where the economic crisis has led to shortages and prohibitive prices.
But it is a problem experienced by many across Africa, and Kenya in particular, where 54% of people live on less than $1 a day.
"I normally lie. I always say that I'm sick at the time of my period," says Soudah Gurhan, a student in Wajir, north-eastern Kenya.
Zainabu Mohammed, a teacher at Wajir's Dambas primary school, says this is the case with many of her female pupils.
"The children that can't afford them miss lessons until their period is over. When they report to classes, they normally say that they were sick because they have no other reason to give out," she says.
It is estimated that an average girl loses more than a full month of classes in a school year.
Zimbabwe's sanitary towel shortage has led to an increase in infections
Those who cannot afford to buy sanitary towels resort to diverse methods, ranging from old pieces of cloth or used blankets to tissue paper or just remaining indoors to contain the menstrual flow.
These methods are not only unhygienic, but a health hazard.
The Girl Child Network, a non-governmental organisation, has been trying to address the problem by providing free sanitary towels in some Kenyan schools.
But Mercy Musomi, its executive director, says it is not enough just to hand out the towels as often the girls have never come across pads before.
"When you give them sanitary towels they ask us: 'How are we going to use it? What will hold it?' For example in the Rift Valley area, some girls folded them and inserted them like tampons," she says.
"Instead of just giving them something that they can't use, we are teaching them first, we've created programmes."
In some African countries, reusable pads are used, but Ms Musomi believes it is out of the question for Kenya to go down that road.
"Up country there is no water. So if they lack even clean water to drink, how are they going to get the water to wash the reusables?"
The government has waived taxes on sanitary ware, but campaigners want them to further reduce the price.
Civil rights groups are also calling on the government to distribute sanitary towels for free to school-going girls.
But as these options are weighed, girls and women in rural Kenya remain at the mercy of market forces.