Girls on the Vanuatu island of Tanna are missing up to a week of school a month because of the difficulty in dealing with menstruation.
Aid workers say the girls' education is being harmed because of a lack of toilets and sanitary items and taboos around the subject.
A water, sanitation and hygiene specialist for CARE International in Vanuatu, Julian Tung, has been helping to install redesigned latrines in 19 schools around the island.
"It's basically a hole in the ground with a vent in it. It's a very common basic technology but we've just installed some basic washing facilities inside the pit latrines, so it's nothing expensive, nothing complicated but what that does it gives the girls some privacy to go in and wash themselves or wash their reusable sanitary pads."
Mr Tung said the topic was often glossed over so the aid organisation has been trying to get the girls to speak out about the challenges they face dealing with their menstrual cycle, without male teachers present.
"Speaking with the girls in a manner that allows them to speak openly or ask questions freely and that has sort of opened it and helped break the taboo and we're also speaking to the boys as well, so that we're helping to challenge this topic."
Mr Tung said children often missed school because they had diarrhoea or other water-borne diseases and he said the changes in toilet design are helping to support all children's education.
He said males were often involved in the planning of school facilities, and it was important they communicate with the children to find out their needs.
"We'd like this to grow and we're encouraging the girls themselves to become champions for menstrual hygiene and encouraging their community to help break the taboo as well, so we'd like this to spread as a standard approach to sanitation."