Schoolgirl absenteeism in Ghana could be cut by half by providing free sanitary towels, a study has shown.

The Oxford University research team found in a six-month trial that with pads and hygiene education, girls were more confident about attending school.

The research was conducted in four villages where the traditional method for period protection was cloth rags.

"It's a taboo subject, [but] we found they were very anxious to try something else," researcher Linda Scott said.

"There girls are so poor that they have to use whatever cloth they can find," she told the BBC's Focus on Africa programme.

"The cloth is so scarce that they only have two pieces of it, so they have to wash it at night and hope that it dries in the morning, which of course in a damp climate it doesn't, so they end up wearing damp and soiled cloths which is not hygienic."

She said in one of the villages, there was only one community toilet, the school had no toilet of its own and there was no running water at all in the village.

"Conventional thinking would be in an environment like this it's not sanitary pads you need it's toilets and plumbing," she said.

"But in fact... it is in those dire circumstances that the pads are most needed and have their biggest effect."