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Clinical Summary

Bacterial Vaginosis in Pregnancy to Prevent Preterm Delivery: Screening

Recommendations made by the USPSTF are independent of the U.S. government. They should not be construed as an official position of the Agency for Healthcare Research and Quality or the U.S. Department of Health and Human Services.

Clinical Summary of U.S. Preventive Services Task Force Recommendation

This document is a summary of the 2008 recommendation of the U.S. Preventive Services Task Force (USPSTF) on screening for bacterial vaginosis in pregnant women. This summary is intended for use by primary care clinicians.

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Population Asymptomatic Pregnant Women Without Risk Factors for Preterm Delivery Asymptomatic Pregnant Women With Risk Factors for Preterm Delivery
Recommendation Do Not Screen
Grade: D
No recommendation due to insufficient evidence.
Risk Assessment

Risk factors of preterm delivery include:

  • African-American women.
  • Pelvic infection.
  • Previous preterm delivery.

Bacterial vaginosis is more common among African-American women, women of low socioeconomic status, and women who have previously delivered low-birth-weight infants.

Screening Tests

Bacterial vaginosis is diagnosed using Amsel's clinical criteria or Gram stain.

When using Amsel's criteria, 3 out of 4 criteria must be met to make a clinical diagnosis:

  1. Vaginal pH >4.7.
  2. The presence of clue cells on wet mount.
  3. Thin homogeneous discharge.
  4. Amine 'fishy odor' when potassium hydroxide is added to the discharge.
Screening Intervals

Not applicable.


Treatment is appropriate for pregnant women with symptomatic bacterial vaginosis infection.

Oral metronidazole and oral clindamycin, as well as vaginal metronidazole gel or clindamycin cream, are used to treat bacterial vaginosis.

The optimal treatment regimen is unclear.1

For a summary of the evidence systematically reviewed in making these recommendations, please go to the full supporting documents.

Copyright and Source Information

This document is in the public domain within the United States.

Requests for linking or to incorporate content in electronic resources should be sent via the USPSTF contact form.

1 The Centers for Disease Control and Prevention (CDC) recommends 250 mg oral metronidazole 3 times a day for 7 days as the treatment for bacterial vaginosis in pregnancy.

Current as of: February 2008

Internet Citation: Clinical Summary: Bacterial Vaginosis in Pregnancy to Prevent Preterm Delivery: Screening. U.S. Preventive Services Task Force. October 2014.

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