Pregnancy or childbirth, is a term that includes human reproductive period of gestation. It begins when a man's sperm fertilizes the egg of the woman and this fertilized egg implants in the uterine wall.
The word adolescence comes from "suffers" which means "absence or lack of maturity," reason, pregnancy is not recommended at this stage of growth.
Adolescence is one of the most difficult step for us as human beings because it is a state of maturity where it seeks a maturity, in which we run the risk of failing or making mistakes that will sniff in our future life.
The teenage pregnancy is already a social, economic and public health of considerable magnitude, both for youth and their children, couples, family, environment and community around them. Some people call teen pregnancy as the "substitution of love for sex."
This problem has been improved by the introduction of issues of sexuality in schools, but not widespread at all educational institutions, for that reason I consider that the number of teenage pregnancies remains high falls.