[The pattern of use of oral contraceptives in Iceland 1965 to 1989.].

Introduction: Around 20% of Icelandic women of childbearing age use oral contraceptives. Knowledge of the health effects of oral contraceptive use and patterns of use is of importance. Patterns of use were studied, according to birth cohorts and age for the years 1965 to 1989.

Material: The source of information was the population based databank of the Cancer Detection Clinic of the Icelandic Cancer Society, where information regarding reproductive factors and birth control exists for over 80% of Icelandic women. Around 74,000 women gave information in the study period.

Results: Over 90% of women born after 1944 had used oral contraceptives. However, 20% had stopped after a year or less. One third had used the pill for more than four years. The age distribution of women taking oral contraceptives changed during the study period. Use decreased in the age groups 30 years or older, whereas it increased in younger women. Of users born in 1960-67, 80% had started before the age of 20 and 33% before the age of 17.

Conclusion: This descriptive study shows that oral contraceptive use is common among Icelandic women and that use under the age of 20 has rapidly increased since the early seventies.