Adolescent fertility rates have declined significantly throughout most countries of the world over the past few decades. Adolescent fertility still remains of concern, however, especially when girls in their early teens have babies. This entry presents information on the magnitude of recent declines, mortality and morbidity risks faced by adolescents who get pregnant and either abort or carry their babies to term, health and developmental risks to children born to young mothers, and some of the social and economic causes and consequences of early motherhood.