Researchers from Indiana University School of Medicine and Regenstrief Institute showed that repeated infection with the organisms that cause chlamydia, gonorrhea and trichomoniasis 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 Dr Wanzhu Tu, associate professor of medicine at the IU School of Medicine and a Regenstrief Institute investigator.
The study involving 381 girls aged 14 to 17 years showed that 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 Tu.
"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 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.
The study appears in the December 2009 issue of Archives of Pediatrics and Adolescent Medicine.