Some girls in Britain are forced to skip school each month because they cannot afford sanitary products.
According to Freedom4Girls, an organisation that works in Kenya but was contacted by a school in Leeds asking for help, women and girls in poverty are forced to improvise when they are on their period.
"I spoke to a woman who could only afford a loaf of bread to feed her children, so she used a slice of bread for her period," founder Nina Leslie said on Wednesday while calling for more government support.
One 11-year-old girl told BBC Radio Leeds she uses socks or toilet paper because her family does not give her any money for tampons or pads.
Campaigners rallied outside the prime minister's Downing Street office on Wednesday, calling for free sanitary products to be given through schools to girls in poverty.
"Toilet paper is free in schools, so why not sanitary products?" MP Jess Phillips said during the protest.
Campaign group Free Periods estimates the initiative would cost £4.78 million ($6.39 million, 5.38 million euros) annually.
A government spokesman said £2.5 billion has been invested this year on the most disadvantaged students, which schools could spend on sanitary products.