Dr. Ledger: I screen these patients every time I do a vaginal exam. But the problem is I’m not going to diagnose any patients who have asymptomatic BV because I don’t do a vaginal exam at every prenatal visit. Hoyme recommends that patients examine themselves twice a week. If they have an alkaline pH, they are to see the doctor right away. If the doctor confirms BV, they are treated.5 However, I think more studies are needed to determine whether twice-weekly screening is appropriate in the United States. Guidelines should not be established until we have some good data.
Dr. Faro: I also screen my patients every time I do a vaginal exam. As for twice-weekly screening, there has not been any research that has statistically shown a cause and effect between BV and preterm delivery (PTD). To come up with screening guidelines for something we aren’t sure is really causing a problem is not in our best interest. Furthermore, we really don’t have good treatments for these women. Metronidazole and clindamycin are only 66% effective, and they are a short-term treatment.6
OBG Management: Can you describe how BV causes preterm delivery?
Dr. Hillier: Although we understand that BV leads to an increased incidence of chorioamnion infection, placental inflammation, and amniotic fluid infection, the mechanisms by which BV causes preterm delivery are not completely understood. Failure to understand the pathophysiology of infection-related PTD has complicated these issues. Most women with BV deliver at term without complication. However, a really important question is why some women with BV deliver preterm. When we are better able to target the subset of women at increased risk—and offer them preventive treatment—I believe we will begin to see successes with clinical trials.
To normalize pH levels, prescribe Aci-jel and/or boric acid vaginal capsules or suppositories.
OBG Management: The current treatment for BV in gravidas and nonpregnant women is metronidazole and clindamycin. Because clinical studies have shown that these medications are not 100% effective, should physicians consider other agents? If so, what would these be?
Dr. Ledger: Certainly. The Europeans have come up with a number of alternate treatments that have lactobacilli in them. These are used to encourage the flora to get back to normal. I know there are researchers in the United States working on this, too. And Secundo Guaschino of Italy recently presented a paper at the seventh annual meeting of the International Infectious Disease Society of Obstetrics and Gynecology in which estrogen therapy for menopausal women resulted in a more normal flora dominated by lactobacilli. Of note, pretreated women with an absence of lactobacilli did not have BV.
Dr. Faro: Yes, researchers are working in this area. It is important to note that if Lactobacillus is the key organism needed to normalize the vaginal flora, the only way you will be able to correct an altered flora is by creating an environment in the vagina that is conducive to the growth of Lactobacillus. But the problem is these patients have such an altered pH that even Lactobacillus cannot compete well with other bacteria. To normalize pH levels, I prescribe either 1 applicator of Aci-jel (Ortho Pharmaceutical Corp, Raritan, NJ) twice a day for 2 to 3 weeks, and/or 600 mg of boric acid vaginal capsules or suppositories twice a day for 14 days.
Dr. Ledger: I think you will find that these agents will not be effective in the long term. But these are things that need to be confirmed by testing.
Dr. Hillier: Current treatment guidelines for BV are based on a substantial body of literature generated over the past 20 years. Both metronidazole and clindamycin have excellent activity against anaerobic bacteria, which are thought to be the primary pathogens among women with BV. Clinical trials have taught us that agents such as sulfa cream or quinolones, which do not have anaerobic activity, yield lower cure rates overall than either metronidazole or clindamycin.7 It is important to note that topical clindamycin, because of its broad-spectrum activity against Lactobacillus and other organisms, causes a temporary overgrowth of E. coli and Enterococcus in the vagina.8 This overgrowth is thought to lead to an increased incidence of early PTD and, perhaps, neonatal infections in women given intravaginal clindamycin treatment during pregnancy. Therefore, it is important for clinicians to remember that intravaginal clindamycin cream is not a recommended treatment by the Centers for Disease Control and Prevention (CDC) for BV during pregnancy.9
OBG Management: Does it follow then that metronidazole and clindamycin do not help reestablish normal vaginal flora?