Pregnancy is the biggest killer of teenage girls worldwide, with one million dying or suffering injury, infection or disease due to pregnancy or childbirth every year, according to a new report from Save the Children.
Babies that are born to younger mothers are at far greater risk and around one million babies born to adolescent girls die every year, according to Save the Children.
Some 222 million women around the world who do not want to get pregnant currently have no access contraception, resulting in 82.3 million unintended or mistimed pregnancies in developing countries every year.
World leaders will meet in London next month for a family planning summit hosted by the UK government and the Bill & Melinda Gates Foundation.
Save the Children is urging them to increase the global availability of contraceptives and empower girls and women to decide whether and when they have children - and how many.
The report reveals that girls under 15 are five times more likely to die in pregnancy than women in their 20s, while babies born to younger mothers are also at far greater risk, and around a million babies born to adolescent mothers die every year.