Sending teen girls periodic text messages reminding them to follow through on their clinic appointments for periodic birth control injections can go a long way toward improving timing and adherence to contraception in an age group that is notoriously noncompliant, according to a small study from the Johns Hopkins Children's Center.

"Our findings suggest that text messaging can help overcome some issues that teens struggle with and pose challenges for the clinicians caring for them, such as keeping clinical appointments, adhering to a tight treatment schedule and regularly taking prescription medications," says study senior investigator and adolescent health expert Maria Trent, M.D., M.P.H. "Results of our study support the notion that clinicians caring for teens should consider capitalizing on this mode of communication for their outreach."

Results of the research, published online May 19 in the Journal of Adolescent Health, overall highlight the largely untapped potential of texting as a means of routine communication between clinicians and teen patients, the team says.

Cell phone use among teens and young adults -- even those from low-income communities -- is ubiquitous, the researchers note and it represents a "low-hanging fruit" opportunity to reach patients directly, bypassing traditional mail and phone call reminders.

The study was conducted among 100 Baltimore girls and young women, ages 13 to 21, receiving contraception via injection every three months and followed over nine months. Each injection provides contraception for three months.

One-half of the patients received standard automated calls on their home phones reminding them of their upcoming appointment, while the other half received personalized daily text messages starting three days prior to their monthly appointment, asking them to text back their responses.

In addition, the mobile phone group also received periodic texts with tips on condom use to prevent sexually transmitted infections, suggestions for maintaining healthy weight and messages urging them to call their nurse with any questions or concerns.

Overall, 87 percent showed up for the first of three injections, 77 percent completed the second cycle, and 69 percent came to clinic for the third and final injection. Because all participants received personal phone calls from a nurse, the study was not equipped to measure differences in show-up rates between those who received standard phone call reminders and those who got text messages.

However, teens who received text-message reminders were more likely to show up for their injections on time than their peers who got traditional reminders -- 68 percent compared with 56 percent for first appointment and 68 percent compared with 62 percent for second appointments. The differences between the two groups, however, dissipated by the third appointment.

Physicians say the timing of injections is critical to how well they work, with protection dwindling if injections are spaced too far apart.

"When teens show up for their follow-up injections is just as important as whether they show up," Trent says.

Trent says that from a public-health point of view, access to effective long-acting contraception is critical to reducing teen pregnancies. Monthly contraceptive injections are one means to do so.