Most studies demonstrate that untreated bacterial vaginosis increases the rate of preterm birth. Despite this, there is no evidence that screening and treatment of asymptomatic bacterial vaginosis nor interpregnancy treatment of endometritis decreases the subsequent rate of preterm birth. However, treatment of symptomatic bacterial vaginosis has been associated with a modest reduction in subsequent preterm birth. Potential mechanisms for this reduction include a decrease in peripheral maternal pro-inflammatory activation of the TH1 inflammatory cascade with treatment, however this direct pathway has not been elucidated. The approved treatment for bacterial vaginosis during pregnancy consists of Metronidazole 500mg BID for 7 days. A more complete understanding of the effect of Metronidazole on maternal inflammation would be useful in designing strategies to reduce the rates of preterm birth.

This study proposes to determine the effect of standard treatment of BV carriage on maternal serum markers of inflammation. This will be accomplished by giving patients with asymptomatic BV either the standard treatment of metronidazole or a placebo for 7 days. Blood will be drawn to compare levels of Interleukins 1 and 6 as well as Tumor Necrosis Factor Alpha.

• Drug: Metronidazole
• Drug: Placebo

• Active Comparator: Subjects who are randomly assigned to receive metronidazole 500 mg po for a period of 7 days following diagnosis of asymptomatic BV.
• Placebo Comparator: Subjects who are randomly assigned to receive a placebo for a period of 7 days following the diagnosis of asymptomatic BV.

Inclusion Criteria:

• 32 weeks gestation or greater
• Multiparity
• No history of preterm birth
• English speaking
• Ability to provide informed consent
• Bacterial vaginosis by gram stain

Exclusion Criteria:

• Acute infections at any site
• Active autoimmune disease
• Current anti-inflammatory use
• Symptomatic bacterial vaginosis
• Previous adverse reaction to metronidazole
• Reports ongoing ethanol consumption