Screening check
Should I be tested for bacterial vaginosis in pregnancy?
Bacterial vaginosis (BV) is a common change in the bacteria of the vagina and has been linked to preterm birth. The US Preventive Services Task Force looked at whether pregnant people without symptoms should be tested. Check what it says for you.
About your pregnancy
For people who are pregnant now. Nothing you enter leaves this page.
What you will see
What the USPSTF says about BV testing in your pregnancy.
Educational only, not medical advice. Talk to your prenatal clinician about symptoms.
Source
US Preventive Services Task Force, April 2020 recommendation on screening for bacterial vaginosis in pregnant persons to prevent preterm delivery.
Validated in
Pregnant people without signs or symptoms of bacterial vaginosis.
Limits
It is not a test and cannot tell whether you have bacterial vaginosis. It does not cover people with symptoms, and it does not judge your preterm risk for you.
What the USPSTF recommends
| Who | Recommendation | Grade |
|---|---|---|
| Pregnant people not at increased risk of preterm delivery | Do not screen for bacterial vaginosis | D |
| Pregnant people at increased risk of preterm delivery | Evidence insufficient to recommend for or against | I |
The USPSTF concluded with moderate certainty that screening pregnant people without symptoms who are not at increased risk has no net benefit in preventing preterm delivery (USPSTF 2020). For people at increased risk, the evidence was insufficient and conflicting. The recommendation applies only to people without signs or symptoms, and it is consistent with the 2008 recommendation (USPSTF 2020).
Who is at increased risk of preterm delivery
Many factors raise the risk of preterm birth, and one of the strongest is a previous preterm delivery, which carries about 2.5 times the odds of another one (USPSTF 2020). People with no history of preterm delivery and no other risk factors count as not at increased risk.
Why it matters
Bacterial vaginosis is found in 5.8% to 19.3% of pregnant women, depending on the group studied (USPSTF 2020). It is often without symptoms, can clear on its own and often comes back, with or without treatment. In pregnancy it has been linked to preterm delivery, early miscarriage, infection of the uterus after birth and low birth weight (USPSTF 2020). About 10% of US live births are preterm, and about two-thirds of infant deaths occur among babies born preterm (USPSTF 2020).
Why screening does not help most people
No studies directly tested whether screening reduces preterm birth. In trials that treated bacterial vaginosis without symptoms in pregnancy, mostly in the general obstetric population, treatment did not clearly lower preterm delivery, and results in higher-risk groups were mixed (USPSTF 2020). Antibiotic treatment can cause stomach upset and vaginal yeast infections. Studies of metronidazole in pregnancy found no increase in birth defects or childhood cancer (USPSTF 2020).
Common questions
What if I have symptoms?
Thin off-white discharge, a fishy odor or both can be signs of bacterial vaginosis (USPSTF 2020). Clinicians routinely test and treat pregnant people who have symptoms, so tell your prenatal clinician.
How is it treated?
Usually with metronidazole or clindamycin, taken by mouth or used as a vaginal gel or cream. The best treatment in pregnancy is unclear, and the CDC publishes current treatment advice (USPSTF 2020).
Also see the syphilis screening check, the gestational diabetes screening check, the blood pressure in pregnancy check, the bacteria in urine check and all screening tests by age.
Sources
- US Preventive Services Task Force. Screening for Bacterial Vaginosis in Pregnant Persons to Prevent Preterm Delivery: US Preventive Services Task Force Recommendation Statement. JAMA. 2020;323(13):1286-1292. www.uspreventiveservicestaskforce.org/uspstf/recommendation/bacterial-vaginosis-in-pregnancy-to-prevent-preterm-delivery-screening
Written and maintained by the uncovermyrisk.com editorial team. We do not have a medical reviewer; every claim links to its primary source above. Last reviewed: 2026-10-30. Spotted an error? See About.