A new study issued this week by the National Bureau of Economic Research links two reality television shows to reduced teen pregnancies in the U.S.

The popular MTV shows “16 and Pregnant” and “Teen Mom” follow the plight of young mothers from the end of their pregnancy to their early days of motherhood as they struggle with homework and hormones, yell at their boyfriends, slam doors on their moms, and try to take care of an infant. In the 18 months after the introduction of the shows a few years ago, Google searches and tweets regarding abortion and birth control increased and teen births in the U.S. decreased 5.7 percent.

That’s a third of the overall decline in teen births during that period. The teen birth rate declined for all age groups of teens and all races and ethnicities.

Melissa S. Kearney (University of Maryland) and Phillip B. Levine (Wellesley College) used data from Google Trends and Twitter to document changes in searches and tweets resulting from the show, Nielson ratings data to capture the locations of viewership, and Vital Statistics birth data to measure changes in teen birth rates. Searches and messages containing “birth control” and “abortion” spiked when new episodes aired.

The teen birth rate in the U.S. has been declining for 20 years, falling from 6.2 percent in 1991 to 2.94 percent in 2012. From 1991 to 2008, the teen birth rate fell 2.5 percent on average per year, but in the next four years, the teen birth rate fell more rapidly, at 7.5 percent on average per year. The “16 and Pregnant” franchise began in June 2009.

“The timing of the introduction of MTV’s '16 and Pregnant' is such that it might conceivably have contributed in some measure to the most recent, very sharp decline,” Kearney and Levine’s report states.

The authors also noted that teen abortion rates fell over the same period of rapid decline in the teen birth rate, suggesting that the shows impacted reduced pregnancies more than a greater use of abortion. But they are careful to admit they did not have sufficient data to evaluate how the shows specifically impacted abortion rates.

Critics of the “16 and Pregnant” and “Teen Mom” series argue the shows glamorize teen pregnancy, turning the young mothers into celebrities. But Kearney and Levine’s study, if correct, shows that MTV communicates with teens in ways that change their behavior, with society-wide consequences that could be positive as well as negative.