From the Journal of Adolescent Health, “Understanding the Recent Decline in Adolescent Fertility in the United States, 2007-2013“:
Purpose: After substantial declines in adolescent birth rates in the 1990s and early 2000s and a stall from 2005-2007, the decline in U.S. adolescent fertility accelerated after 2007. Modeling fertility change using behavioral data can provide insights for adolescent policy development.
Methods: Nationally representative household data from multiple rounds of the National Survey of Family Growth (NSFG) were combined with method-specific contraceptive failure rates to calculate a Pregnancy Risk Index (PRI) which summarizes the risk of pregnancy based on level of sexual activity in the last 3 months, contraceptive use patterns, and method-specific contraceptive efficacy. We calculated the PRI for women aged 15-19 in 2007, 2009, and 2012 and validated the index by comparing trends in the estimated PRI to the observed national adolescent pregnancy and birth rates since 2007. Changes in the PRI were decomposed statistically into change resulting from shifts in sexual activity and shifts in contraceptive use.
We’ve discussed how the teen pregnancy and birth rates are at all-time lows. But why? Researchers set out to answer that.
They used data from the National Survey of Family Growth to calculate a “Pregnancy Risk Index”. The PRI calculates the risk of pregnancy based on sexual activity in the last month, contraceptive use, and contraceptive specific efficacy and failure rates. They calculated the PRI in 2007, 2009, and 2012.
They found that that sexual activity didn’t decline. What changed was contraceptive use. Use of the pill went up from 26% to 35%, as did IUDs (1.3% to 2.7%), condoms (49% to 56%), and even withdrawal (15% to 20%). The use of multiple methods increased from 23% to 34%. The percentage of kids reporting no contraceptive use dropped from 20% to 13%.
This led to the PRI dropping 5% every year from 2007 to 2012. Further, about 94% of the decline in the pregnancy risk index was attributable to contraceptive use.
It’s not that kids are having much less sex. It’s that they’re practicing much safer sex. This is good. Contraception works.
