Half of urban teen girls acquire STIs within two years of first sexual activity

The study appears in the December 2009 issue of Archives of Pediatrics and Adolescent Medicine.

The researchers followed 381 girls enrolled at ages 14 to 17 years and found that repeated infection with the organisms that cause chlamydia, gonorrhea and trichomoniasis also was very common.

"Depending on the organism, within four to six months after treatment of the previous infection, a quarter of the women were re-infected with the same organism," said Wanzhu Tu, Ph.D., associate professor of medicine at the IU School of Medicine and a Regenstrief Institute investigator.

Within two years, about three-quarters of participants with an initial sexually transmitted STI were diagnosed with a second STI, although not necessarily of the same type. Within four years of an initial STI, virtually all (92 percent) of the participants had a subsequent STI.

"To our knowledge, this study provides the first data on the timing of the initial STI and subsequent STI following the onset of sexual activity in urban adolescent women," said Dr. Tu.

The study also found that screening for STI may not be initiated until several years after sexual activity begins, especially for girls with earlier onset of sexual activity.

"This is important because many clinicians are reluctant to address sexual activity with younger teens, and may miss important prevention opportunities," said J. Dennis Fortenberry M.D. M.S., professor of pediatrics at the IU School of Medicine, and senior author of the study.

The study focuses on lower income urban adolescents; a group characterized by early onset of sexual activity, multiple sexual partners, and high STI rates.

As a result of their findings, the researchers call for STI screening in sexually active teenage girls within a year after first intercourse and for retesting of infected girls every 3 to 4 months. Continuing surveillance may be necessary, they conclude, because of the continuing high risk of infection even if the first rescreening test result is negative.

Co-authors of the study are Byron E. Batteiger, M.D.; Sarah Wiehe, M.D., M.P.H.; Susan Ofner, M.S.; Barbara Van Der Pol, Ph.D.; Barry P. Katz, Ph.D.; Donald P. Orr, M.D.; and J. Dennis Fortenberry, M.D., M.S., all of the IU School of Medicine. Drs. Wiehe, Katz and Orr are also Regenstrief Institute affiliated scientists.