Sexual initiation, contraceptive use, and pregnancy among young adolescents.

OBJECTIVE To present new data on sexual initiation, contraceptive use, and pregnancy among US adolescents aged 10 to 19, and to compare the youngest adolescents' behaviors with those of older adolescents. METHODS Using nationally representative data from several rounds of the National Survey of Family Growth, we performed event history (ie, survival) analyses to examine timing of sexual initiation and contraceptive use. We calculated adolescent pregnancy rates by single year of age using data from the National Center for Health Statistics, the Guttmacher Institute, and the US Census Bureau. RESULTS Sexual activity is and has long been rare among those 12 and younger; most is nonconsensual. By contrast, most older teens (aged 17-19) are sexually active. Approximately 30% of those aged 15 to 16 have had sex. Pregnancy rates among the youngest teens are exceedingly low, for example, ∼1 per 10 000 girls aged 12. Contraceptive uptake among girls as young as 15 is similar to that of their older counterparts, whereas girls who start having sex at 14 or younger are less likely to have used a method at first sex and take longer to begin using contraception. CONCLUSIONS Sexual activity and pregnancy are rare among the youngest adolescents, whose behavior represents a different public health concern than the broader issue of pregnancies to older teens. Health professionals can improve outcomes for teenagers by recognizing the higher likelihood of nonconsensual sex among younger teens and by teaching and making contraceptive methods available to teen patients before they become sexually active.