Determinants for non-use of contraception at first intercourse; a study of 10841 young Danish women from the general population.

Based on interview data from 10841 Danish women aged 20 to 29 years, determinants for non-use of contraception at first intercourse (NU) were studied. One-fourth of the women (n = 2704) reported NU, whereas condoms and oral contraceptives were used by, respectively, 59% and 15%. NU decreased with the birth year of the first male partner (OR = 3.6; 95% CI: 2.8-4.8 for <or=1954 vs. 1968-1974) mainly in favor of condom use. Other determinants were the birth cohort of the woman (OR = 1.4; 95% CI: 1.0-1.9 for 1961-1962 vs. 1970-1972) and the calendar year of the first intercourse (OR = 1.4; 95% CI: 1.2-1.7 for 1985-1986 vs. 1987-1992), both initially in favor of oral contraception and later in favor of condom use, whereas young age at first intercourse was associated with a high prevalence of NU (OR = 1.8; 95% CI: 1.4-2.1 for <or=14 years vs. >or=17 years) at the expense of both oral contraception and condom use. Finally, NU was found to predict high-risk sexual behavior in terms of subsequent multiple sex partners, non-use of condoms, and induced abortion.