BV in Pregnancy: Risks, Treatment and What to Do
What the preterm birth link actually means, which treatments are used, and why this one needs your midwife rather than an online order.
Part of the Bacterial Vaginosis condition guide.
Please read first: Access Doctor does not supply BV treatment during pregnancy. This guide is here so you know what to expect and what to ask — but if you are pregnant with symptoms, contact your GP, midwife or a sexual health clinic. They can assess you properly with your full maternity record in front of them.
Key fact: BV in pregnancy is associated with an increased risk of preterm birth — but association is not the same as cause, the absolute risk stays low for most women, and the great majority of affected pregnancies proceed entirely normally.
Speak to Your Maternity Team
If you are pregnant with vaginal symptoms, your GP, midwife or local sexual health clinic is the right route. For non-pregnancy BV, Access Doctor offers a GPhC-regulated online consultation with pharmacist independent prescribers.
See BV treatment options →Why BV is common in pregnancy
Pregnancy changes the vaginal environment substantially. Oestrogen levels rise, which increases glycogen in the vaginal lining and alters the balance of the microbiome. Normal discharge increases in volume too — a change called leucorrhoea that most pregnant women notice and that is entirely healthy.
The result is a period where the vaginal ecosystem is in flux and where changed discharge is both more likely and harder to interpret. BV is common in pregnancy, and it is also more commonly suspected than it is present, because normal pregnancy discharge gets mistaken for it.
The risks, in proportion
This is the part most women want addressed directly, and it deserves an honest rather than an alarming answer.
BV during pregnancy has been associated in observational studies with a number of adverse outcomes:
- Preterm birth — delivery before 37 weeks. This is the best-established association.
- Premature rupture of membranes — waters breaking before labour begins.
- Late miscarriage — pregnancy loss in the second trimester.
- Low birth weight.
- Postpartum endometritis — infection of the womb lining after delivery.
- Infection after caesarean section.
How to hold this. These are associations found across populations, not predictions about you. BV is common and preterm birth is comparatively uncommon, which means most women with BV in pregnancy deliver at term. Association also does not establish causation — it is possible that BV and preterm birth share underlying causes rather than one producing the other. That distinction is not merely academic: it is precisely why treating BV has not reliably reduced preterm birth in trials of low-risk women.
What follows from that is a measured position. BV in pregnancy is worth reporting, worth assessing and usually worth treating if you have symptoms. It is not a reason for alarm, and it is not something you should be blamed for or feel you caused.
Telling BV from normal pregnancy discharge
Increased discharge in pregnancy is normal. The features that suggest something more than that are the same ones that characterise BV outside pregnancy.
| Feature | Normal pregnancy discharge | Possible BV |
|---|---|---|
| Volume | Increased — expected and healthy | Increased |
| Colour | Clear or milky white | Grey or dull off-white |
| Consistency | Thin to slightly thick, no coating quality | Thin and watery, coats the vaginal walls |
| Smell | Mild or none | Fishy, stronger after sex |
| Itching | Absent | Usually absent — if prominent, consider thrush |
The single most useful discriminator remains odour. Increased clear or white discharge without smell is very likely to be normal. Increased grey discharge with a fishy smell is worth reporting. Fuller detail is in our guide to BV symptoms, discharge and smell, and the thrush comparison — thrush is also more common in pregnancy — is in BV vs thrush.
Contact your maternity unit immediately if you have any fluid leaking or gushing from the vagina, vaginal bleeding, abdominal pain or regular tightenings, a fever, or reduced fetal movements. These need urgent assessment and are not something to manage at home. In an emergency, call 999.
How BV is treated in pregnancy
Symptomatic BV in pregnancy is generally treated. The principles are the same as outside pregnancy, with some specific adjustments.
1
The diagnosis is confirmed first
Because normal pregnancy discharge and thrush both muddy the picture, clinicians are more likely to confirm BV with a swab or pH testing in pregnancy rather than treating on symptoms alone.
2
Standard-course metronidazole is usually used
Metronidazole is used in pregnancy where the benefit outweighs the risk. A standard course — typically 400mg twice daily for five to seven days — is the usual choice.
3
High single doses are avoided
The single 2g metronidazole dose is specifically avoided in pregnancy. This is one of the clearest differences from non-pregnancy prescribing.
4
Vaginal preparations may be considered
Both oral and vaginal routes have been used in pregnancy. Which is chosen depends on your history, gestation and your clinician's judgement — it is not a decision to make from a website.
If you have had a previous preterm birth, your maternity team may take a different approach, since the evidence for treating BV is stronger in that group than in low-risk pregnancies. Make sure your history is known.
On breastfeeding. Metronidazole passes into breast milk and can give it a bitter taste, which occasionally causes feeding difficulties. It is not a reason to avoid treatment, but vaginal preparations produce much lower exposure and are sometimes preferred. Raise it with your prescriber rather than deciding alone.
Why asymptomatic BV is not routinely screened
It seems intuitive that if BV is linked to preterm birth, all pregnant women should be screened and treated. Trials have tested exactly that, and the results did not support it.
In pregnant women at low risk of preterm delivery, treating asymptomatic BV did not reduce adverse pregnancy outcomes. In women with a previous preterm delivery, treatment showed more benefit. That difference is why UK practice does not screen everyone but does take BV seriously in women with symptoms or with a relevant obstetric history.
Not routine
Universal screening for asymptomatic BV in pregnancy
Treat
Symptomatic BV in pregnancy, under clinical care
Avoided
Single 2g metronidazole dose during pregnancy
Why we will not treat you online
Access Doctor supplies BV treatment to non-pregnant women following an online consultation. We do not supply it in pregnancy, and it is worth being clear why rather than simply declining.
The diagnosis needs more care
Normal pregnancy discharge, thrush and BV overlap more in pregnancy. An online questionnaire is a weaker tool here than it is otherwise.
Prescribing choices change
Dose, route and which preparations are appropriate all shift in pregnancy, and depend on gestation and obstetric history we do not hold.
Your maternity record matters
A previous preterm birth changes management substantially. Your midwife or GP has that record; we do not.
Red flags need examination
Leaking fluid, bleeding or pain need in-person assessment the same day, and no online service can provide that.
None of this means you should put up with symptoms. It means the right route is your GP, midwife or a sexual health clinic — all of whom will treat this as routine rather than alarming.
What you can safely do yourself
While you arrange an appointment, a few things help and none of them carry risk.
- Stop douching if you do it. It worsens the imbalance and is the most consistently identified modifiable risk factor for BV.
- Drop perfumed products. Scented washes, bubble bath, vaginal deodorants and scented wipes all disturb vaginal pH. Plain water externally is enough.
- Do not use leftover antibiotics from a previous course, and do not take anything prescribed for someone else.
- Avoid over-the-counter BV products without advice — including lactic acid gels, boric acid and probiotics. Boric acid in particular should not be used in pregnancy.
- Note the pattern. When symptoms started, what the discharge looks like, whether there is odour. It makes the appointment faster and more useful.
- Mention any previous preterm birth unprompted — it genuinely changes the approach.
On natural remedies. The evidence for boric acid, probiotics and similar options is limited even outside pregnancy, and boric acid is specifically unsafe in pregnancy. Our review of what does and does not work is in BV gels compared: prescription vs OTC — but during pregnancy, take the advice of your maternity team over anything you read, including us.
BV Treatment Outside Pregnancy
If you are not pregnant, complete a short online consultation and our GPhC-registered pharmacist independent prescribers will assess which treatment suits you.
Start a BV consultation →Frequently Asked Questions
Is BV dangerous in pregnancy?
BV in pregnancy has been associated with an increased risk of preterm birth, late miscarriage, premature rupture of membranes and infection of the womb lining after delivery. The absolute risk for any individual woman remains low, and most pregnancies affected by BV proceed normally, but it is a reason to have symptoms assessed rather than ignored.
Can I take metronidazole while pregnant?
Metronidazole is used in pregnancy where the benefit outweighs the risk, and standard courses are considered acceptable. High-dose regimens such as the single 2g dose are avoided in pregnancy. This must be a decision made by a clinician who knows you are pregnant, not a self-treatment decision.
Can I order BV treatment online while pregnant?
No. Access Doctor does not supply BV treatment in pregnancy. Pregnancy changes both the assessment and the management, so treatment should come from your GP, midwife or a sexual health clinic who can review your full maternity record.
Does BV cause miscarriage?
BV has been associated with an increased risk of late miscarriage in some studies, but an association is not proof that BV causes it, and the great majority of women with BV in pregnancy do not miscarry. It is one of several reasons to have symptoms reviewed by your maternity team.
Should asymptomatic BV be treated in pregnancy?
Routine screening and treatment of women without symptoms is not recommended, because trials in low-risk pregnancies have not shown it improves outcomes. Symptomatic BV is generally treated, and women with a history of preterm birth may be managed differently by their maternity team.
Is BV more common in pregnancy?
BV is common in pregnancy, and hormonal changes alter both vaginal pH and the amount of normal discharge. That overlap makes it harder to judge symptoms yourself, which is another reason to have changed discharge assessed rather than self-diagnosed.
Can BV affect my baby?
BV does not directly infect the baby. The concern is indirect, through the association with preterm birth and premature rupture of membranes. Babies born at term to mothers who had BV are not otherwise affected by it.
Completing the treatment
For non-pregnant women, Access Doctor supplies BV treatment following an online consultation with a pharmacist independent prescriber. If you are pregnant, please use your GP, midwife or sexual health clinic instead — the products below are shown for information, not for use in pregnancy without clinical advice.
Bacterial vaginosis · Rx
Metronidazole 400mg Tablets
First-line oral antibiotic for BV. Not supplied by us during pregnancy.
View product →Bacterial vaginosis · Rx
Zidoval Vaginal Gel
Metronidazole 0.75% gel. Not supplied by us during pregnancy.
View product →Bacterial vaginosis · Rx
Dalacin 2% Cream
Clindamycin vaginal cream. Not supplied by us during pregnancy.
View product →Self-test · Pharmacy
Canestest Self-Test
Checks vaginal pH at home. A negative result does not replace maternity assessment.
View product →References
- National Institute for Health and Care Excellence. Clinical Knowledge Summaries: Bacterial vaginosis. 2025. cks.nice.org.uk
- Carey JC, Klebanoff MA, Hauth JC, et al. Metronidazole to Prevent Preterm Delivery in Pregnant Women with Asymptomatic Bacterial Vaginosis. New England Journal of Medicine, 2000. nejm.org
- British National Formulary. Metronidazole — pregnancy and breastfeeding. bnf.nice.org.uk
- NHS. Bacterial vaginosis. nhs.uk
- British Association for Sexual Health and HIV. National guideline for the management of vaginal discharge. bashh.org
Medical disclaimer: This article is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional for diagnosis and treatment. In a medical emergency, call 999.