The United Nations says youth-friendly, culturally appropriate education is needed to combat high teenage pregnancy rates across the globe.
About 16 million girls under 18 years of age give birth each year across the world and 3.2 million have unsafe abortions, according to United Nations Population Fund (UNFPA).
Dr Annette Sachs Robertson, UNFPA Pacific director and representative, has told Radio Australia's it is a lost opportunity when girls have babies "before their time".
"They're unable to fulfil their full potential in terms of education..., their contribution to their families and to themselves, and to the economy," she said.
The UNFPA is using World Population Day on July 11 to urge nations to help in "breaking the cycle" of teenage pregnancy with targeted education and reproductive health services.
More than 500 million of the world's 600 million girls are in developing countries, according to the UNPF.
Ms Robertson says teenage births are still "very high" in the Marshall Islands, Vanuatu and Solomon Islands despite declining rates over the past 10 years.
"Significant attention has been paid to them by their governments and by other development partners but they started at very high rates in the first place and that's taking some time to decline," she said.
She says adolescent pregnancies also put pressure on families who are already struggling financially.
"In the Pacific, the wider family will generally take care of the babies, particularly if they're unmarried girls," she said.
"If the family is under the poverty line, that puts a huge stress on the family."
"Sometimes the girls will have to leave school to look after their babies and that in itself is a loss for that particular girl."
The UNPF says pregnancy and childbirth complications are the leading causes of death among teenage girls aged 15 to 19, particularly in developing countries.
Ms Robertson says improvements in education provide some hope, as girls are staying in school longer are less likely to become pregnant.
"This has one of the greatest impacts actually on teenage pregnancies," she said.