Seren Boyd from Christian charity Tearfund told Premier that toilets are vital for women's education: "Teenage girls when they reach puberty and they start their periods, many miss a week, a month of school, and of course when they get older and it goes on, they drop out of school altogether.
"So the simple addition of a proper toilet block in your school if you're a teenage girl means the difference between having an education or not.
"One of the schools we visited which just had a new block installed complete with a changing room, had 65 girls re-enrol in school in just two months."
She said a lack of bathrooms increases the chance that women will spend their life in hard labour or a forced marriage.
Speaking about women in India, Seren Boyd said they were at risk of physical attack because of a lack of toilets: "Women especially were pushing to have toilets installed in their homes, and that's because in India particularly culture dictates that women cannot be seen to go out into the bushes to relieve themselves, so they have to wait for darkness."
Toilet Twinning, part of Tearfund, provides toilets, clean water and hygiene education in some of the poorest countries.
The #BigPush wants to raise awareness that one in three people worldwide still do not have somewhere safe and clean to go to the toilet, with woman particularly affected by the lack of sanitation.
Listen to Premier's Hannah Tooley speak to Seren Boyd here:
