To determine the changes in sexual, reproductive and contraceptive behaviour of adolescent girls attended for the first time at a family planning centre (FPC) over two time-periods.

A descriptive, retrospective study with analytic components.

All the adolescent girls attended on their first visit to the Massamagrell (Valencia) FPC during the 10 years from April 1, 1986 to March 31, 1996 (n = 728).

Dividing the two five-year periods, there were educational activities in schools and institutional campaigns to stop unwanted pregnancies, sexually transmitted diseases (STD) and AIDS.

In the second period more adolescent girls made their first visit to the FPC, with a similar mean age, less pregnancies, deliveries and abortions, and a later start to sexual activity. There was less time between the start of sexual relations and their first visit to the FPC; they used habitually and from the start of their sexual relations more effective contraception.

Adolescent girls attending a FPC for the first time showed a change in their sexual, reproductive and contraceptive behaviour, in that they were at less risk of pregnancy, STD and AIDS.