[15] Risk factors include douching, new or multiple sex partners, antibiotics, and using an intrauterine device, among others.

[1] Although about 50% of women with BV are asymptomatic,[19] common symptoms include increased vaginal discharge that usually smells like fish.

[2] The discharge coats the walls of the vagina, and is usually without significant irritation, pain, or erythema (redness), although mild itching can sometimes occur.

By contrast, the normal vaginal discharge will vary in consistency and amount throughout the menstrual cycle and is at its clearest at ovulation—about two weeks before the period starts.

BV is a risk factor for viral shedding and herpes simplex virus type 2 infection.

[22][24] In addition, bacterial vaginosis as either pre-existing, or acquired, may increase the risk of pregnancy complications, most notably premature birth or miscarriage.

[25][26] Pregnant women with BV have a higher risk of chorioamnionitis, miscarriage, preterm birth, premature rupture of membranes, and postpartum endometritis.

[22][24] Healthy vaginal microbiota consists of species that neither cause symptoms or infections, nor negatively affect pregnancy.

[31] Douching is strongly discouraged by the U.S. Department of Health and Human Services and various medical authorities, for this and other reasons.

[31] BV is a risk factor for pelvic inflammatory disease, HIV, sexually transmitted infections (STIs), endometriosis, and reproductive and obstetric disorders or negative outcomes.

[34] A longitudinal study published in February 2006, in the American Journal of Obstetrics and Gynecology, showed a link between psychosocial stress and bacterial vaginosis persisted even when other risk factors were taken into account.

[37][38] The diamines putrescine and cadaverine, which are the decarboxylation products of arginine and lysine amino acid metabolism, respectively, are also present in BV and may contribute to the fishy smell of the condition as well.

These swabs can be tested for: Differential diagnosis for bacterial vaginosis includes the following:[42] The Center for Disease Control (CDC) defines STIs as "a variety of clinical syndromes and infections caused by pathogens that can be acquired and transmitted through sexual activity.

Hence, the presence of clue cells and gram variable coccobacilli are indicative or diagnostic of bacterial vaginosis.

[49] The Nugent score is now rarely used by physicians due to the time it takes to read the slides and requires the use of a trained microscopist.

View multiple fields (note that this factor is less important – scores of only 0–2 are possible) DNA hybridization testing with Affirm VPIII was compared to the Gram stain using the Nugent criteria.

[53] Screening during pregnancy is not recommended in the United States as of 2020 because " the US Preventive Services Task Force concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening for bacterial vaginosis in pregnant persons at increased risk for preterm delivery".

It also found that such treatment may lead treated sexual partners to report increased adverse events.

[19][58] Other antibiotics related to metronidazole, including tinidazole and the newer secnidazole, are also approved and used to treat BV.

[66] The preferred probiotics for BV are those containing high doses of lactobacilli (around 109 CFUsTooltip Colony-forming units) given in the vagina.

[68] LACTIN-V is a live biopharmaceutical medication containing the vaginally important Lactobacillus crispatus which is under development for the treatment of bacterial vaginosis and recurrent urinary tract infections.

[71] One study found that vaginal irrigations with hydrogen peroxide (3%) resulted in a slight improvement, but this was much less than with the use of oral metronidazole.