Primary Sources: Using Cigarettes and Marijuana at an Early Age May Put Girls at Risk for Pregnancy

Photograph of cigarette butts in an ash tray.

Brief report: Pregnant by Age 15 Years and Substance Use Initiation Among U.S. Adolescent Girls.” Journal of Adolescence, Vol. 35, No. 5 (October 2012).

What it’s about: Researchers at the Washington University School of Medicine in St. Louis wanted to know what types of substance use might put teenage girls at risk for becoming pregnant at a very young age (under 15 years old). To find out, they studied data from the National Youth Risk Behavior Survey, which is conducted every two years by the Centers for Disease Control and Prevention. The survey takes stock of the risky health behaviors of U.S. high school students.

Why read it: There’s a lot of research that shows an association between teen pregnancy and unhealthy consequences for the young moms and their babies. The consequences are worse when teens get pregnant at 15 or younger.

Biggest takeaways for youth workers: Only 3 percent of the teens in the researchers’ sample had ever been pregnant by age 15. But among those who had, marijuana use and smoking were common, even at very young ages. Thirty percent of girls who had been pregnant had also smoked marijuana by age 12. Half had smoked cigarettes by age 12.  Only 8 percent of girls who had never been pregnant had smoked marijuana by that age, and one-fifth percent had used cigarettes.

Overall, the likelihood of getting pregnant by age 15 was highest for girls who had smoked marijuana when they were 10 or younger.

The researchers point out some limitations of their analysis. The Youth Risk Behavior Survey stopped asking about teen pregnancy after 2003. So the results of this study, which uses data from the 1999, 2001 and 2003 surveys, is somewhat dated. Also, because of the type of study this is, the researchers can’t say that substance use causes teen pregnancy. And the study doesn’t include responses from teens who had dropped out of school, who may have higher pregnancy rates than youth who stay in school. The researchers view their study as a starting point for future investigation of how substance use influences teen pregnancy, and how this knowledge may help us find better ways to prevent very young teens from getting pregnant.

Additional references: You can learn more about the Youth Risk Behavior Surveillance System on the CDC website. Curriculum-Based Support Group is an evidence-based program for children and preteens who are at high risk for using drugs and alcohol at an early age.

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