However, even this does not offer a long-term solution if there is no social service intervention to help girls appreciate the value of contraception, says author Catherine Stevens-Simon, M.D., of the University of Colorado Health Sciences Center and The Childrens Hospital.
"We suspect that these contraceptives are uniquely effective with teenagers because they are currently the only methods that make the default (do-nothing) position as nonpregnant (rather than pregnant)," she and her co-investigators explain.
The study is published in the July issue of American Journal of Preventive Medicine.
Stevens-Simon and her colleagues looked at pregnancy rates in 350 girls participating in the Colorado Adolescent Maternity Program, which covered prenatal and postnatal care and emphasized healthy habits, consistent contraceptive use, regular school attendance and planning for the future.
As part of the program, the teens were encouraged to choose a birth control method during the period after their delivery and before they became fertile again.
One year after delivery, none of the girls who had chosen Norplant, a slow-release hormonal contraceptive that is implanted under the skin and lasts four to five years, was pregnant.
In contrast, 11 percent of those who started on Depo-Provera, a hormone injection whose effects last about three months, became pregnant in the first year. Twenty-five percent of those who decided to use oral contraceptives and 38 percent of those who decided against birth control became pregnant.
"Despite guaranteed access to equally effective contraceptives and strong encouragement to use them
Contact: Nora Brunner
Center for the Advancement of Health