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Bacterial vaginosis (BV) is one of the most common things we see in pregnancy, and for most people it is very manageable.
It is worth treating properly, because BV is linked to a higher chance of preterm birth.1 The reassuring part is that there are effective, pregnancy-safe ways to deal with it.
As a vulvovaginal specialist clinic, our approach is to work out why the microbiome has shifted and match a pregnancy-safe treatment to you, working alongside your midwife or obstetrician.
Here is the full picture: what BV does in pregnancy, what works, what is safe to use, and the one thing to avoid.
Is BV in pregnancy dangerous?
BV is associated with a higher risk of preterm birth and related problems, including premature rupture of the membranes and low birth weight.1
Associated is the key word. It raises the odds, it does not guarantee a problem, and plenty of women with BV have full-term, healthy babies.
Because BV is both common and treatable, the sensible response is to sort it out calmly and well, not to panic.
Why BV happens in pregnancy
Pregnancy reshapes the vaginal environment. Rising oestrogen loads the vaginal walls with glycogen, which is food for protective Lactobacillus bacteria – so many pregnancies actually become more lactobacilli-dominant.
But the immune system also softens in pregnancy so the body does not reject the baby, and that shift can give disruptive bacteria an opening. When protective species lose ground, BV can take hold.
This is a shift in an ecosystem, not a sign of poor hygiene, and it is not your fault. It is exactly the kind of imbalance a microbiome-focused approach is built to correct.
How BV can affect the pregnancy
The concern with BV is inflammation. The disruptive bacteria that take over can produce enzymes – sialidases among them – that break down protective mucus, including the cervical mucus plug.
That can let bacteria travel upward and set off an inflammatory response, which is thought to be one of the triggers for early labour. We cover this in exactly how BV causes preterm birth.
Keeping the microbiome balanced, the mucus plug intact and inflammation low is the goal – which is why the approach matters as much as the ingredient.
Why antibiotics alone often are not the answer
Here is something that surprises people. Treating symptomless BV with antibiotics has not reliably reduced preterm birth in trials.2
That is also why routine screen-and-treat of low-risk pregnancies with no symptoms is not recommended – blanket antibiotic treatment simply has not been shown to help.3
A big reason is that antibiotics clear bacteria but do not rebuild the protective community or tackle the biofilm, so BV comes back – recurrence sits at around half within a year.4
This is not an argument to ignore BV. It is the argument for treating the microbiome, not just the moment – which is exactly what we do.
Pregnancy-safe treatment options
The good news is that several effective options are considered safe in pregnancy. These are the ones we work with, matched to the person and the trimester.
Dequalinium chloride (Fluomizin)
Dequalinium is a broad-spectrum antiseptic vaginal tablet that clears BV about as well as antibiotics – it matched metronidazole in a 2024 randomised trial and clindamycin in an earlier one.5,6
It works locally with very little absorbed into the body, disrupts Gardnerella biofilm, and is a well-tolerated option in pregnancy.
Probiotics and prebiotics
Lactobacillus probiotics help restore and hold the protective community, and are a useful part of cure-and-prevent strategies for vaginal dysbiosis.7
Vaginal lactulose is a gentle prebiotic that feeds protective lactobacilli, and pairs well with a probiotic approach.
Antibiotics, where they fit
The standard antibiotics, metronidazole and clindamycin, are considered safe in pregnancy and have their place, especially for clear symptoms. We simply pair or follow them with microbiome repair so the result holds.
You can see the pregnancy-safe options we point people to in our pregnancy-safe treatment notes.
The one to avoid: boric acid
We never recommend boric acid in pregnancy. It is a useful BV treatment when you are not pregnant, but it is a reproductive toxicant, and vaginal use in pregnancy has been linked to birth defects.8,9
As a rule, do not put anything in the vagina during pregnancy that has not been confirmed as pregnancy-safe.
The My Vagina approach
In our clinic we see a lot of pregnant patients who want to sort BV without reaching for antibiotics they feel uneasy about.
As vulvovaginal specialists, there is a great deal we can do – matching a pregnancy-safe option to what a comprehensive vaginal microbiome test actually shows, and looking at the wider picture like diet, immune support and the drivers behind the imbalance.
We do this alongside your maternity team, not around them – the two fit together well. You can book with a My Vagina naturopath for individualised, pregnancy-safe support.
What this means for you and your baby
The takeaway is reassuring: BV in pregnancy is common, most pregnancies are fine, and there are effective, pregnancy-safe ways to treat it well.
Some symptoms do need a maternity team promptly rather than home treatment. Contact your midwife, obstetrician or maternity unit if you have any of these:
- Fluid leaking from the vagina, or a gush or trickle of water.
- Regular tightening, cramping or contractions before 37 weeks.
- Any vaginal bleeding.
- Fever, or feeling generally unwell.
- Reduced or changed baby movements.
This is general information, not a substitute for personalised medical advice.
Frequently asked questions
Can BV cause preterm birth or miscarriage?
BV is associated with a higher risk of preterm birth and related complications, so it is worth treating.
That said, it raises the odds rather than causing a problem in every case, and most women with BV go on to have healthy, full-term babies.
What BV treatments are safe in pregnancy?
Dequalinium (Fluomizin), Lactobacillus probiotics and vaginal lactulose are all considered pregnancy-safe, and the antibiotics metronidazole and clindamycin are too.
Boric acid is the notable exception – it should be avoided in pregnancy.
Do probiotics help BV in pregnancy?
Yes – Lactobacillus probiotics help rebuild and hold the protective community, which is the part antibiotics miss. We use them as part of a microbiome-first approach, and they are pregnancy-safe.
Should I be screened for BV in pregnancy?
Routine screening of low-risk pregnancies with no symptoms is not recommended, because blanket antibiotic treatment picked up this way has not been shown to prevent preterm birth.
If you have symptoms, or a higher risk of preterm birth, testing and treatment make sense – and a comprehensive microbiome test tells you exactly what to target.
Why does my BV keep coming back in pregnancy?
Because antibiotics clear the bacteria but do not rebuild the protective community or clear the biofilm. Pairing treatment with microbiome repair – probiotics, prebiotics and addressing the drivers – is what makes it hold.
What to do next
If you are pregnant and think you have BV, it is worth sorting properly with someone who treats it all day. A comprehensive test shows what is there, and a pregnancy-safe plan clears it and helps keep it gone.
Ask Aunt Vadge’s Assistant, the chat widget in the bottom-left of your screen, or book a consultation with one of our naturopaths. For any of the red-flag symptoms above, contact your maternity team straight away.
- Kenfack-Zanguim J, Kenmoe S, Bowo-Ngandji A, et al. Systematic review and meta-analysis of maternal and fetal outcomes among pregnant women with bacterial vaginosis. Eur J Obstet Gynecol Reprod Biol. 2023;289:9–18.
- Carey JC, Klebanoff MA, Hauth JC, et al. Metronidazole to prevent preterm delivery in pregnant women with asymptomatic bacterial vaginosis. N Engl J Med. 2000;342(8):534–540.
- 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.
- Bradshaw CS, Morton AN, Hocking J, et al. High recurrence rates of bacterial vaginosis over the course of 12 months after oral metronidazole therapy and factors associated with recurrence. J Infect Dis. 2006;193(11):1478–1486.
- Raba G, Durkech A, Malík T, et al. Efficacy of dequalinium chloride vs metronidazole for the treatment of bacterial vaginosis: a randomized clinical trial. JAMA Netw Open. 2024;7(5):e248661.
- Weissenbacher ER, Donders G, Unzeitig V, et al. A comparison of dequalinium chloride vaginal tablets (Fluomizin) and clindamycin vaginal cream in the treatment of bacterial vaginosis: a single-blind, randomized clinical trial. Gynecol Obstet Invest. 2012;73(1):8–15.
- van de Wijgert J, Verwijs MC. Lactobacilli-containing vaginal probiotics to cure or prevent bacterial or fungal vaginal dysbiosis: a systematic review. BJOG. 2020;127(2):287–299.
- Acs N, Bánhidy F, Puhó E, Czeizel AE. Teratogenic effects of vaginal boric acid treatment during pregnancy. Int J Gynaecol Obstet. 2006;93(1):55–56.
- Mittelstaedt R, Kretz A, Levine M, et al. Data on safety of intravaginal boric acid use in pregnant and nonpregnant women: a narrative review. Sex Transm Dis. 2021;48(12):e241–e247.
