What needs to change?
Pregnancy prevention campaigns are aimed at changing girls' behaviors, implicitly blaming the girl for pregnancies at a young age, according to the report.
"Such approaches and thinking are misguided because they fail to account for the circumstances and societal pressures that conspire against adolescent girls and make motherhood a likely outcome of their transition from childhood to adulthood," wrote Osotimehin.
The report makes recommendations to "build girls' human capital" and offer "opportunities so that motherhood is not seen as their only destiny."
It cited a study that found when Kenyan schools began providing children with uniforms free of charge, the dropout rate decreased by 18% and pregnancy rates fell 17%, showing that access to education was an effective tool.
In Guatemala, Mayans are the country's most disadvantaged group, with problems of child marriage. A support network for rural Mayan girls provided safe space and taught leadership skills. Results showed girls in the program stayed in school and had much lower pregnancy rates than the national average.