This exploration of adolescent pregnancy focuses on adolescents whose pregnancies are undesired. The physical and psychic transformations of puberty and adolescence may be experienced differently in different social contexts. The prolongation of school attendance in Western societies means that most adolescents remain financially dependent on their parents. But greater sexual freedom in the society at large has been reflected in an increase in early sexual activity among adolescents. Wider use of contraception has not completely eliminated prenatal pregnancy among adolescents. Adolescent pregnancies have actually declined in France as a proportion of all pregnancies carried to term, from 4% to 1.5-2% in the past 10 or 15 years. But in 1986, 42.5% of all induced abortions were performed on adolescents. Among causes of unwanted pregnancy in adolescents are their frequent inability to believe that they may be at risk of pregnancy, or that pregnancy can result from the 1st sexual intercourse. The episodic nature of sexual relations, the lack of ready availability of contraception, and specific shortcomings of different methods are factors in the frequent failure of adolescents to protect themselves against undesired pregnancy. Adolescents may become pregnant out of loneliness or to prove that they are women, or as a result of incest or prostitution. Adolescents who seek abortions are those who have discovered and acknowledged their pregnancies before the 12th week and had the courage to inform their parents and obtain legal permission for the abortion. Pregnancy terminations are more frequent in more advantaged societal sectors with more structured family life. The moral shock and sense of failure associated with abortion are often deeply felt by adolescents. Their experience is greatly influenced by the attitudes of those around them. Adolescents who carry their pregnancies to term are those who have not sought abortion in the 1st 12 weeks. Often they refuse to admit they might be pregnant. But adolescents from disadvantaged environments may wish to continue the pregnancy in order to attain social status. Most parents eventually resign themselves to the pregnancy. Adolescents who are closely monitored usually have normal pregnancies and deliveries. The proportion of adolescent mothers who place their infants for adoption has declined. Most of the infants kept by their mothers are entitled to 2 sets of social prestations, the allowances for the young infant and for single parents. School nurses have an important potential contribution in informing students about sexuality and contraception and in assisting those who become pregnant.