Ms. Lowry’s cautionary tale seems to have made an impression on at least some viewers. A new economic study of Nielsen television ratings and birth records suggests that the show she appeared in, “16 and Pregnant,” and its spinoffs may have prevented more than 20,000 births to teenage mothers in 2010.

The paper, to be released Monday by the National Bureau of Economic Research, makes the case that the controversial but popular programs reduced the teenage birthrate by nearly 6 percent, contributing to a long-term decline that accelerated during the recession.

“It’s thrilling,” said Sarah S. Brown, the chief executive of the National Campaign to Prevent Teen and Unplanned Pregnancy, a nonprofit group in Washington. “People just don’t understand how influential media is in the lives of young people.”