Bacterial Vaginosis


  • Patients may be assymptomatic
  • Thin fishy smelling vaginal discharge may be present – especially after intercourse
  • vaginal inflammation is minmal
  • the discharge may cause local irritation but isn’t on the whole itchy


It’s caused by mixture of bacteria.

Most of the sepcies are present in small numbers in normal women but when there becomes too many the natural lactobacilli flora of the vagina is disrupted and bacterial vaginosis occurs.

Theres and increase vaginal pH (pH>4.5)as a result of the overgroth of mixed anaerobic organisms

  • increases risk of preterm birth
  • increases risk of infective complications following gynae surgery 

BV is most common cause of vaginal discharge in women of reproductive age.

  • Gardnerella vaginalis is commonly found in women with BV but it’s presence alone is not a diagnosis of BV as it occurs as a commensal in 30-40% of aymptomatic woment
  • OTher organisms include Prevotella species, Myoplasma hominis and Mobiluncus species.

BV is “sexually associated” rather than truely “sexually transmitted” it used to be thought that it occurred in virgins but actually they were probably engaging in oral or digital intercourse – theres not been any cases in truely sexually inexperienced women.

There’s evidence that condoms decrease the incidence of BV

Investigation / Diagnosis

Microscopy for “clue cells” – epithelial cells densely covered with bacilli

Mix the discharge iwht potassium hydroxide and theres a fishy amonia like smell this is a “Positive Amine Test”

Make your diagnosis from clincal findings and the positive amine test


  • Metronidazole 400-500mg bd for 7 days (use 400mg bd for five days in pregnancy  -theres never been a adverse event but try to avoid it in the first trimester – think about Oral clindamycin 300mg BD for five days in that case)
  • Otherwise you can use tetracycline, clindamycin, or douching with povidone-iodine
  • Topical clindamycin 2% cream for 7days once at night is an alternative –

Treating the partner

  • Probably don’t need to treat male partners
  • But treat female partners.