Bacterial vaginosis in pregnancy – everything you need to know

by Dr Brenna Weaver · July 20, 2022

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Reviewed by Dr Melanie Davis-Hall on July 20, 2022

Bacterial vaginosis in pregnancy | The Lowdown
Get the lowdown on what to do if you think you're experiencing bacterial vaginosis during pregnancy, including treatment and prevention.

What’s the lowdown?

  • Bacterial vaginosis (BV) is a common condition caused by an imbalance of vaginal bacteria
  • Many people never have symptoms, so often won’t know they have BV, even during pregnancy
  • The most common symptom of BV is a fishy smelling, watery discharge 
  • There are many risk factors that can predispose you to bacteria vaginosis, including the use of intimate washes, being sexually active, having multiple sexual partners, and lifestyle factors like smoking
  • Whilst bacterial vaginosis is usually harmless, in pregnancy it can increase your risk for preterm delivery and labour, miscarriage and infections of your womb 
  • Bacterial vaginosis doesn’t always require treatment. Management of the risk factors for BV usually clears things up but it is easily treatable with antibiotics if needed. 

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Bacteria=Bad, right? WRONG! Especially when referring to your vagina. With over 500 different species of bacteria that call your vagina ‘home’, these microbes are essential for a fully functional reproductive system and indeed, body. Which is exactly what we’re looking for during one of the body’s most stressful encounters – pregnancy. 

What is bacterial vaginosis?

Bacterial vaginosis (BV) is an imbalance, or over-dominance, of one or more bacterial groups living within your vagina. No one likes a dictatorship, least of all your vagina, so when the balance is wobbled, everything tends to function a little less well than it should. One of the most common bacteria to call your vagina ‘home’ are Lactobacilli which keeps the other bacteria in check! A few things do occasionally catch Lactobacilli off guard and allow other bacteria to dominate, leading to symptoms we’d all rather avoid. This isn’t necessarily led by one type of bacteria, as a few species have been noted in research to be particularly fond of taking over.

Bacterial vaginosis symptoms in pregnancy

A hallmark symptom of BV is a grey or white fishy-smelling discharge which commonly occurs after having sex. Up to 50% of women won’t have any symptoms at all and currently, screening people for BV who don’t have symptoms isn’t recommended. 

Confirming the diagnosis of BV can be done based on your symptoms and an examination by your doctor or nurse. Sometimes this can include a simple test to check the pH of your vagina with a strip of specially coated paper and a cotton wool swab of the vagina and discharge. This can be looked at under a microscope to identify clue cells (cells from your vaginal wall that change to a fuzzy appearance due to bacterial coating).

A change in discharge is often associated with sexually transmitted infections (STIs), so get an STI test if you think you might be at risk, and remember that condoms are still the only contraceptive method that protects you from STIs.

BV is not considered an STI but being sexually active without barrier protection such as a condom may increase your risk of BV and BV recurrence. Other risk factors include having an IUS or IUD, using intimate ‘hygiene’ products (please don’t!) and recent oral antibiotic treatment (which often kills off some bacteria required to keep the balance and may lead to other problems such as thrush). We have an indepth blog on the causes of bacterial vaginosis and treatment here* for you to learn more. 

Risks of having bacterial vaginosis whilst pregnant

More often than not BV is only temporary, swiftly leaving your body without any symptoms or complications. However if you’re pregnant and bacterial vaginosis doesn’t clear up, there are some potential complications. 

Premature labour (labour starting before 37 completed weeks of pregnancy), spontaneous miscarriages and infections of the womb (both before and after delivery) are complications associated with BV during pregnancy. Luckily these complications rarely occur, especially if you are not showing symptoms or have been treated. Currently, in the UK you will only be tested for BV if you are experiencing symptoms as studies have shown no change in outcomes for pregnant women treated for BV without symptoms. If you think you might have BV and you are pregnant, you should speak to your doctor or midwife. 

BV is associated with getting STIs more readily as your vaginal tissues may be damaged by the bacterial imbalance. STIs hold their own set of nasty risks and complications whilst pregnant which can affect both you and your baby, sometimes very seriously. So if you’re in doubt about if your discharge or other symptoms are due to BV or an STI, get medical advice. 

Can bacterial vaginosis prevent pregnancy?

In short, no. One study found that BV had no direct effect on conception or fertility but there is a lack of research on the subject. There also isn’t enough evidence to link BV with other conditions such as pelvic inflammatory disease (PID) which may cause damage to your reproductive organs, making falling pregnant more challenging. More research is needed to figure out the role that BV and the normal bacteria in your vagina may play in fertility. 

Treatment for bacterial vaginosis in pregnancy

Prevention of bacterial vaginosis is better than cure! So if you’re pregnant, trying to conceive, or even trying to avoid pregnancy, these interventions may help you avoid BV: 

  1. Less sex (Don’t panic, move to point two!) 
  2. Sex with a condom
  3. Don’t use a vaginal douche, your vagina is self-cleaning. Instead use clean, warm water to clean the vulva – outside of your vagina 
  4. Stop smoking. Smoking is not only a risk factor for BV but is detrimental to your overall health and your pregnancy

If you’re pregnant and think you may have BV, speak to your doctor. Medical treatment is usually straightforward with antibiotics, a cream or gel applied into the vagina, or oral tablets. Antibiotics such as clindamycin and metronidazole are prescribed for 5 to 7 days. Your body may sort the imbalance out on its own and antibiotics may not be needed, but it is important to discuss this with your doctor or healthcare practitioner in pregnancy. 

Recurrence of BV is often a problem, which sucks. This study suggests that rates of recurrence are as high as 80% three months after effective treatment. Management of risk factors and stopping what might be causing the problem in the first place is important for managing recurrent BV. 

Over the counter self treatment options like relactagel are also available and safe to use in pregnancy to prevent recurrent BV. Speak to your doctor or health care practitioner to find what’s best for you. However, Relactagel should be avoided if you’re trying to become pregnant as semen may be neutralized by the lactic acid gel.

When to speak to a doctor

If you have symptoms of BV and are pregnant, getting a doctor’s input is the best way to go as correct testing and proper treatment can be done quickly to avoid any complications. 

Similarly, if you’re trying to fall pregnant and have recurrent BV symptoms a GP should be able to talk you through addressing any risk factors and when to seek advice when pregnant.

  1. Bagga, R. &. Aroura, P.,; 2020. Genital Micro-Organisms in Pregnancy. Front Public Health, 225(8).
  2. Chen, X. et. al., 2021. The Female Vaginal Microbiome in Health and Bacterial Vaginosis. Front. Cell. Infect. Microbiol.
  3. Coudray, M. &. M. M., 2020. Bacterial Vaginosis – A Brief Synopsis of the Literature. European journal of Obstetrics and Gynaecology and Reproductive biology , Volume 245, pp. 143-148.
  4. NHS, 2018. Bacterial Vaginosis. [Online]
    Available at: [Accessed 8 June 2022].
  5. NHS, 2022. Complications of Pelvic inflammatory disease. [Online] Available at: [Accessed 13 June 2022].
  6. NICE, 2018. Scenario: Bacterial vaginosis in women who are pregnant. [Online] Available at: [Accessed 12 June 2022].
  7. Taylor, B. et. al., 2013. Does Bacterial Vaginosis Cause Pelvic Inflammatory Disease? Sexually Transmitted Diseases, 40(2), pp. 117-122.
  8. Turpin, R. et. al., 2021. Bacterial Vaginosis and Behavioral Factors Associated With Incident Pelvic Inflammatory Disease in the Longitudinal Study of Vaginal Flora. The journal of infectious disease, 224(12), pp. 137-144.
  9. Amabebe,E & Anumba, DO. 2018.The Vaginal Microenvironment: The Physiologic Role of Lactobacilli. Frontiers in medicine. 5: 181
  10. Ralph, S. et al. 1999 Influence of bacterial vaginosis on conception and miscarriage in the first trimester: cohort study BMJ  319(7204): 220–223.
  11. Coudray, MS & Purnima, M. 2020 Bacterial Vaginosis – A Brief Synopsis of the Literature Eur J Obstet Gynecol Reprod Biol.; 245: 143–148.

Dr Brenna Weaver MBChB (WITS) is a South African trained doctor, who became passionate about women’s health whilst working in under-resourced, rural communities, doing everything from Caesarean sections to contraceptive drives.