Professors David Paton and Sourafel Girma of The University of Nottingham used local health data to study the effects of the availability of emergency birth control at pharmacies on conception rates and the diagnosis of STIs in teens age 18 and under.
On average, areas operating a pharmacy emergency birth control program had an overall increase of 5 percent in the rate of STIs among teenagers -- 12 percent in those age 16 and under -- while the program was associated with a small increase in the number of teens pregnant, the study says.
Since 2000, local authorities in England have been encouraged to offer emergency birth control free of charge, over-the-counter at pharmacies, to teenagers age 16 and under. Many local authorities have introduced the emergency birth control program but implemented them at different times, and some have decided against it altogether, the researchers say.
"Our study illustrates how government interventions can sometimes lead to unfortunate unintended consequences," Paton says in a statement. "The fact that STI diagnoses increased in areas with emergency birth control schemes will raise questions over whether these schemes represent the best use of public money."
The findings are published in the Journal of Health Economics.