Authored By: Dr. K. Shilpi Reddy

Clinical Director – Obstetrics & Gynaecology, Fertility Specialist & High-Risk Pregnancy Care, Minimal Invasive Surgeon (Mini Lap, Laparoscopy, Robotic Team)

Bacterial vaginosis is a vaginal infection caused by bacteria. It is the most common cause of abnormal vaginal discharge that happens in reproductive-age women. It can cause a “fishy” odor and vaginal irritation in some women. Others may not have any symptoms.


Most of the females with bacterial vaginosis will not have any symptoms but when they have, it includes-

  • Burning feeling while micturation
  • Fishy smell mostly after sex
  • Itching
  • Thin white, gray, or green discharge


It is rarely seen in females who are not sexually active. It most commonly affects-

  • Pregnancy
  • Unprotected Intercourse
  • Have an intrauterine device (IUD)
  • Have multiple sex partners
  • Have a new sex partner
  • Have a female sex partner
  • Use douches
  • Smoking
  • Perfumed bubble baths, vaginal deodorants, and few scented soaps
  • Washing underwear with strong detergent


BV is due to an imbalance of natural vaginal bacterial flora. Why this happens is not clear.

The role of bacteria

Bacteria is present allover our bodies, but some are beneficial while others are harmful. These bacteria become infectious when number of harmful bacteria increases.

The vagina is house for mostly “good” bacteria and some harmful bacteria. BV occurs when the harmful bacteria outgrows the good bacteria in number.

A vagina should contain bacteria called lactobacilli. These bacteria produce lactic acid, making the vagina slightly acidic. This prevents growth of other bacteria.

Acidity of vagina decreases if levels of lactobacilli decreases leading to growth of other bacteria’s. However, exact relationship of these harmful bacteria with BV is not known.


Bacterial vaginosis doesn’t generally cause complications. Sometimes, having bacterial vaginosis may lead to:

During pregnancy– In pregnant women, bacterial vaginosis is linked to loss of pregnancy, early rupture of amniotic membranes, Chorioamnionitis, premature deliveries and low birth weight babies due to preterm labours.

After Delivery-Postpartum Endometritis, an irritation or inflammation of uterine lining.

Sexually transmitted infections– Bacterial vaginosis makes women more susceptible to sexually transmitted infections, like HIV, herpes simplex virus, chlamydia or gonorrhea. If you have HIV, bacterial vaginosis increases the chances of passing on the virus to your partner.

Infection risk after gynecologic surgery- such as hysterectomy or dilation and curettage (D&C).

Pelvic inflammatory disease (PID) – Bacterial vaginosis can sometimes cause an infection of the uterus and the fallopian tubes therefore the risk of infertility increases.

Studies have shown that success rate of IVF decreases in BV.


  • Minimize vaginal irritation- by using mild or nonscented soaps and tampons or pads.
  • Don’t douche- douching disrupts the vaginal balance and may increase your risk of vaginal infection. 
  • Avoid Sexually transmitted diseases- Use a male latex condom, limit your number of sex partners.
  • Always wipe from front to back instead of back to front after using the bathroom.
  • Wear cotton or cotton-lined underwear. Bacteria thrive in moist environments. Cotton helps wick away moisture.


The doctor will:

  • Ask about your medical history- about previous STIs, etc.
  • Do an overall physical exam
  • Do a pelvic exam- for signs of infection, condition of pelvic organs
  • Take a sample of discharge from your vagina to look for  bacteria
  • Test your vaginal pH. A vaginal pH of 4.5 or higher is associated with bacterial vaginosis.


Often it remains asymptomatic, but women with signs and symptoms should take treatment to avoid complications.

Often antibiotics (metronidazole, clindamycin, tinidazole) are required to treat BV. This could be a tablet or a cream or gel you put into your vagina. Most females need to take treatments for 5 to 7 days. Finish full course of medicines, even if the symptoms go away. Incomplete medications course can lead to recurrence.

Since BV can be spread through sex, so it is advisable to avoid sexual contact till treatment is finished. Female sexual partners should see their doctor to find out if they need treatment.

IUDs users with BV can opt for other forms of contraception.

To treat bacterial vaginosis, following medicaions can be prescribed:

  • Metronidazole- This is given as oral forms mostly. Metronidazole is also be given as a topical gel to insert into the vagina. It is the most commonly used antibiotic. It is preferred over other antibiotics if the woman is breastfeeding or pregnant.
  • Clindamycin -This medicine is available as a cream that you insert into your vagina. Clindamycin creams are known to weaken latex condoms- so take adequate precautions for atleast 3 days after stopping the treatment.
  • Tinidazole-This medication is taken orally. Tinidazole reacts with alcohol, so avoid alcohol during treatment and for at least three days after completing treatment.
  • Secnidazole -This is an antibiotic you take orally in one dose. 

Generally it is not necessary to treat an infected woman’s male sexual partner, but it can spread among female sexual partners, so female partners should be tested and treated accordingly. It’s especially important for pregnant women with symptoms to be treated to decrease the risk of premature labour.


Around one-third of women whose symptoms disappear with treatment will have a recurrence within 3 months, and half will have a recurrence within 6 months.

If more than three episodes occur within 12 months, the doctor may prescribe a vaginal metronidazole gel to use twice a week for 3 to 6 months.

While current research shows there may be some benefit to probiotic therapy, more research is needed on the subject.

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