TUESDAY, Aug. 28, 2001 (HealthDayNews) -- The one drug used to treat the most common curable sexually transmitted disease in young women increases a pregnant woman's chances of giving birth early, a new National Institutes of Health study says.
But the U.S. Centers for Disease Control and Prevention (CDC) says the study used a larger dose of the drug, metronizadole, than the center recommends for the treatment of trichomoniasis. And the CDC says it has no plans to change that recommendation.
"Trichomoniasis is a fairly common infection," says study author Dr. Mark Klebanoff, director of the Division of Epidemiology, Statistics and Prevention Research for the National Institute of Child Health and Human Development in Bethesda, Md.
"In many teaching hospitals, it's seen in as many as one-in-six women, and it seems to be especially prevalent in African-American women, though no one is exactly certain why," he says.
Caused by the bacterium Trichomonas vaginalis. trichomoniasis infects both men and women but is usually symptomless in men.
In women with symptoms, the infection causes a frothy, yellow-green vaginal discharge with a strong odor and may cause discomfort during intercourse and urination. Irritation and itching of the genital area can also occur, as well as lower abdominal pain, although that's rare.
An estimated 5 million new cases of the disease occur each year in women and men, says the CDC.
Klebanoff says other studies linked trichomoniasis and either premature birth or low birth weight in pregnant women.
"Pregnant women who have the organism may give birth to babies with lower birth weight and there's a higher incidence of stillbirth, but trichomoniasis has not been highly researched with respect to pregnancy outcome," he says.
National Institutes of Health researchers turned to metronizadole to curtail premature births and to combat the infection. Instead, their study found the drug nearly doubled the chances for premature births in women who had no symptoms of trichomoniasis.
The study looked at 640 pregnant women diagnosed with trichomoniasis but without symptoms. The researchers gave 8 grams of metronizadole over two weeks to 315 women, while 289 received a placebo. Of the women who got the drug, 60 delivered their babies approximately one month early, while only 31 of the women treated with the placebo delivered early.
Klebanoff says while the premature babies did quite well, "it's not the ideal situation."
"The results were quite surprising to us since we expected the opposite results, and we discontinued the study early at the recommendation of the outside monitoring panel," he says.
The findings were published earlier this month in the New England Journal of Medicine.
Dr. Emily Koumans, a medical epidemiologist for the CDC's Division of Sexually Transmitted Disease Prevention in Atlanta, says, "We actually recommend a lower daily dose of metronizadole spread out over a week. The regimen, which works is 500 milligrams of metronizadole over one week or a single 2-gram dose."
"What they [Klebanoff and his colleagues] did in terms of the usage of this drug is not something we recommend, and we don't think we need to change our recommendations," Koumans says
Klebanoff says he isn't sure why metronizadole caused the premature births.
"We do know that the organism was eradicated by the medicine, and we surmised that perhaps the death of T. vaginalis organisms following treatment provoked an immune system response that stimulated early labor. But since most of the women were treated several months prior to labor, an acute response to the death of the organism does not seem to follow logically."
What to Do: For more information on trichomoniasis, see the CDC, or the American Social Health Association.
