Adolescent pregnancy is a worldwide health problem, which is associated with multiple maternal and fetal complications. According to WHO, adolescence begins at age 10 and ends at approximately 19 years of age. Adolescent pregnancy has increased in the last decade, which carries risks of biological, psychological and social harm. Pregnant adolescents may develop disorders such as anemia, hypertension, infections, toxemia, preterm delivery, threatened abortion, among others. Likewise, the newborn may have low birth weight and severe complications that can lead to death; even if it survives, it may have sequelae such as mental retardation and neural tube closure defects. Preterm delivery, which occurs before 37 weeks of gestation, is considered the main cause of neonatal morbidity and mortality, as well as neurological disorders. A factor associated with this is maternal age under 17 years. Although there are many factors involved in preterm delivery, it is important to know them in order to detect them in time and thus establish prevention strategies.