An international charity has launched an interactive sex education app in Sierra Leone as health experts warn the coronavirus lockdown could cause a surge in unwanted teenage pregnancies.

During the 2014-2016 Ebola outbreak, a 9-month lockdown in Sierra Leone led to a jump in pregnancies among girls and young women as school closures and economic hardship increased sexual abuse and exploitation, as well as consensual sex.

Ramatu Jalloh, Save the Children's advocacy and communications director in the country, said the app — which takes the form of an interactive game — aimed to help avert a repeat of that trend.

"Our concern is that if we weren't addressing those issues that made them unsafe at home then we could possibly have high risks of the same thing occurring," she told the Thomson Reuters Foundation by phone.

School closures and economic hardship could see increased risks for women and girls across Africa including higher rates of unwanted pregnancy, gender-based violence, and child marriage, experts have warned.

Schools do not teach sexual health education in Sierra Leone, and online misinformation combined with community taboos around sex and sexuality often make it difficult for young people to access reliable information.

"We felt that we could kill two birds with one stone by attracting their attention through a medium that they liked ... and providing them with trustworthy information that will help them make informed choices around sex," Jalloh said.

Players of the game encounter situations linked to sexual health and coronavirus measures, and are offered two choices on the best way to move forward. The focus is on prioritising education, debunking myths, and sharing support contacts.

"Your friend just had her first period. Does that mean she is ready to give birth?" one question says. "My classmate just walked by our kitchen window! Let's go and say hi," says another, focused on social distancing rules under lockdown.

Emma Kargbo, 16, from Sierra Leone's capital Freetown, said that connecting with teenagers through technology was a good way to spread information and get people engaged.

"It teaches us about contraceptives and other ways we can be protected," she said in a Save the Children statement.

(Reporting by Amber Milne; Editing by Helen Popper. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, that covers the lives of people around the world who struggle to live freely or fairly. Visit http://news.trust.org)