Contraceptive use at first intercourse is associated with subsequent sexual behaviors

Objective: Women's contraceptive use at first sexual intercourse (FSI) may be associated with subsequent sexual behaviors. We examined associations between contraceptive methods used at FSI and subsequent number of life-time partners, induced abortions and sexually transmitted infections (STIs). Study design: During 2011-2012, we collected questionnaire data from a random sample of women aged 18-45 years from Denmark, Norway and Sweden. We used logistic regression and discrete-time proportional hazards models to estimate odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (CIs), comparing different contraceptive methods used at FSI in the whole study sample and in women with FSI in 2001 or later [when emergency contraceptive pills (ECPs) were available without prescription]. Results: Of 45,361 women in the study sample, those who did not use contraception at FSI (n=8155; 18.0%) were more likely than condom users to have >= 11 lifetime partners (OR=1.34; 95% CI 1.27-1.42), induced abortions (HR=1.62; 95% CI 1.53-1.71) and STIs (HR=1.15; 95% CI 1.10-1.20). ECP users (n= 440, 1.0%) were more likely than condom users to have >= 11 lifetime partners (OR=1.76; 95% CI 1.40-2.22), induced abortions (HR=1.44; 95% CI 1.11-1.86) and STIs (HR=1.84; 95% CI 1.56-2.16). A similar pattern was seen in safe periods/withdrawal users. The associations did not change among women with FSI in 2001 or later (n=14,445). Conclusions: Compared with condom use, contraceptive nonuse, safe periods/withdrawal use and ECP use at FSI were associated with subsequent number of sexual partners, induced abortions and STIs. (C) 2019 Elsevier Inc. All rights reserved.