In many countries around the world, girls are often married before they hit puberty. In African countries this is especially widespread: one in three girls are married before their 18th birthday, the highest rate in the world.  

Aside from the social and developmental challenges this presents it also has a very real economic costs, according to new research by the World Bank spanning 12 countries in the region. The study shows that child marriage costs these economies $63bn in lost earning potential and human capital, primarily by cutting girls' education short. 

“Primary education for girls is simply not sufficient. Girls reap the biggest benefits of education when they are able to complete secondary school, but we know that girls very often don’t stay in school if they marry early,” says Quentin Wodon, the principal author of the report.

Keeping girls in school is also shown to be the most effective way of preventing child marriage. The report shows that each year of secondary education reduces the likelihood of girls marrying before they reach 18 years of age by at least five percentage points.

In a region of the world also facing the fastest rate of population growth, preventing early marriage and ensuring higher education levels for women have been shown to be among the most effective means of lowering fertility rates while also decreasing childbirth mortality rates among very young mothers.