TUESDAY, March 13 (HealthDay News) -- Far too few sexually active young women are getting tested for chlamydia, an oversight that could lead them down a perilous path to severe health consequences, including infertility, later in life.

A new survey from the U.S. Centers for Disease Control and Prevention found that only 38 percent of sexually active girls and women were screened for this common sexually transmitted disease (STD) in the year prior to being questioned. Chlamydia often infects men and women without causing symptoms.

Not only that, another new study finds that only a small proportion of men and women got the recommended follow-up test once they had tested positive for chlamydia. Re-infection with chlamydia is common if partners remain untreated. In those women who are left untreated, chronic pelvic pain and ectopic pregnancies can result, along with infertility.

Both reports were to be presented Tuesday at the National STD Prevention Conference in Minneapolis, as are two additional studies outlining ways clinics and providers might improve on these numbers.

According to Dr. Gail Bolan, director of the CDC's division of STD prevention, an estimated 2.8 million new cases of chlamydia occur each year in the United States.

The CDC recommends annual testing for sexually active women aged 25 and under, as well as retesting either three months after initial treatment for chlamydia or during their next regular health care visit in the year following treatment, said Bolan, who spoke at a Tuesday news conference.

With only about one third of young women getting tested for chlamydia, two-thirds (9 million) are going without, noted study author Dr. Karen Hoover, a medical epidemiologist with the CDC. She called the results "alarming."

Slightly more encouraging, she said, was the news that some groups at particularly high risk for chlamydia infection actually had higher testing rates. This included black women (55 percent got tested), those with more than one sexual partner (47 percent) and people who had no health insurance (41 percent) or relied on government-subsidized insurance (50 percent).

Women who received some sort of reproductive health care, such as contraception, a Pap smear for cervical abnormalities or a pregnancy test were also more likely to get tested compared with women who received no such care (45 percent vs. 4 percent). Older women also had higher testing rates.

"This suggests that we may be moving in the right direction," Hoover noted.

The study authors had no data on chlamydia testing in men as routine testing in this population is not recommended by the CDC, Hoover said.

"There is insufficient data to support this recommendation," she said, although retesting rates among men "will probably be the subject of future analyses."

A second study, based on a laboratory data from almost 64,000 men and women who had tested positive for chlamydia, found that only 11 percent of men and 21 percent of women went for their recommended retest within six months of the original positive results.

Among those who got a follow-up test, one-quarter of men and 16 percent of women were positive.

"Retesting rates were much lower than we had expected," said study author Kelly Morrison Opdyke, of Cicatelli Associates Inc., a non-profit organization.

Again, though, certain demographic groups were more likely to get retested, including younger people (under 25), those visiting family planning clinics (as opposed to STD clinics) and health centers, including health centers at universities or colleges.

Retesting rates also declined over the study period, which spanned 2007 through 2009, although Hoover said researchers weren't able to explain this drop.

Two additional studies found success in boosting re-testing rates by using relatively simple follow-up and reminder systems.

One system, which included email and telephone reminders to students visiting the University of Buffalo's student health center in New York, managed to boost re-testing rates for chlamydia and gonorrhea from 17 percent to 86 percent in just one semester.

Chlamydia accounted for most of the infections detected. Here, retesting rates jumped from 16 percent to 89 percent.

Another study used pop-up screens on electronic medical records to remind providers that a patient needed to be re-tested. The system was conceived after researchers noted low re-testing rates, even among women who visited a health care provider one to six months after their initial treatment. In this case, testing for gonorrhea and chlamydia increased from 70 percent to 86 percent.

More information

The U.S. Centers for Disease Control and Prevention has more on chlamydia.