BV in Pregnancy: Which Treatments Are Safe, and What Happens If You Leave It Untreated

Yes, BV in pregnancy can be treated safely. If you have symptoms, it is worth getting checked rather than waiting for them to clear on their own. CDC recommends treating pregnant people who have symptomatic BV, usually with a seven-day course of metronidazole or clindamycin.

A positive BV test when you have no symptoms is different. It does not automatically mean you need antibiotics. Your OB or prenatal provider can look at the result alongside your pregnancy history and decide what makes sense.

TL;DR: Key takeaways

• Symptomatic BV during pregnancy should be treated with antibiotics. The usual oral regimens are taken for 7 days.
• Metronidazole is a standard first-line option during pregnancy, including the first trimester. Clindamycin is another option.
• Tinidazole should be avoided during pregnancy. Some other BV products also do not have enough pregnancy safety data.
• Routine screening for BV when you have no symptoms is not recommended for preventing preterm birth.
• BV is associated with preterm birth and other pregnancy complications, but having BV does not mean you will have a premature baby.
• Bleeding, leaking fluid, regular contractions before 37 weeks, or fever with pelvic pain need prompt medical attention.
• Pregnancy changes the treatment decision. If you think you have BV, your OB or prenatal provider should be involved rather than treating yourself with an old prescription or an over-the-counter product.

Pregnant with BV symptoms and unsure what to do next? Try August AI's free symptom checker to think through your symptoms in under 2 minutes. For pregnancy-specific treatment decisions, always work with your OB or prenatal provider. They can review your symptoms alongside your pregnancy history, order appropriate testing, and prescribe pregnancy-safe antibiotics when warranted. If you cannot reach your OB and have concerning symptoms like bleeding, leaking fluid, contractions before 37 weeks, or fever with pelvic pain, seek in-person care immediately.

BV in pregnancy is common, and it is not an STI

BV happens when the normal balance of bacteria in the vagina changes. It is common during the reproductive years, including pregnancy, and it is not classified by the CDC as a sexually transmitted infection.

That does not mean sex has nothing to do with BV. Sexual activity is associated with BV, and having a new or multiple sex partners can increase the risk. But you did not get BV from being "dirty," and it is not caused by poor hygiene.

You also cannot catch BV from a toilet seat, swimming pool, or shared bedding. If you are pregnant and notice a new fishy odor, thin gray or white discharge, or irritation, do not assume it is just another pregnancy change. Normal pregnancy discharge is usually clear or milky and does not have a strong fishy odor.

A positive BV result does not always mean you need antibiotics

This is where BV in pregnancy gets confusing.

CDC recommends treating pregnant people who have symptomatic BV because symptomatic infection has been associated with pregnancy complications, including preterm birth and premature rupture of membranes.

But screening everyone for BV when they have no symptoms is a different question. Routine screening of asymptomatic pregnant people has not been shown to prevent preterm birth, so it is not recommended for that purpose.

The 2021 CDC STI Treatment Guidelines recommend treating symptomatic pregnant women and say routine screening of asymptomatic pregnant women, whether they are at high or low risk for preterm delivery, is not recommended as a way to prevent preterm birth.

The U.S. Preventive Services Task Force reached a similar conclusion in 2020. It recommends against screening people without symptoms who are not at increased risk for preterm delivery. For people at increased risk, such as someone with a previous preterm birth, the evidence was considered insufficient to recommend for or against screening.

So if a test comes back positive when you feel completely normal, do not start antibiotics from an old prescription just because the result says BV. Talk to your OB or prenatal provider. Your pregnancy history matters here.

That is also why BV is not simply another item on the routine checklist alongside your blood work and your 8-week ultrasound.

What does BV look like during pregnancy?

BV often causes:

• Thin white or gray discharge
• A fishy or unusual vaginal odor
• Odor that may be more noticeable after sex
• Burning when you urinate
• Mild vaginal irritation

Some people have no symptoms at all.

The tricky part is that pregnancy itself changes vaginal discharge. Normal pregnancy discharge, called leukorrhea, often becomes heavier. It is usually clear, white, or milky and should not have a strong unpleasant odor.

Yeast infections are different too. They are more likely to cause intense itching, irritation, and thick white discharge. A fishy odor points more toward BV.

Still, symptoms cannot confirm BV by themselves. Other vaginal infections and some STIs can look similar. A clinician may need to examine you or take a vaginal sample.

That matters even more during pregnancy because choosing the wrong treatment can mean treating the wrong infection or missing something that needs closer monitoring.

If you are dealing with a confusing change in discharge, the information on infections during pregnancy can help you understand what is common and what deserves a call to your provider.

Does BV increase the risk of preterm birth?

Yes. BV has been associated with several pregnancy complications, including preterm birth, premature rupture of membranes, intra-amniotic infection, and postpartum endometritis.

CDC also notes that babies born to people with BV are more likely to be born prematurely or at a low birth weight.

That sounds scary, but a BV diagnosis does not mean you are going to have a premature baby.

Most pregnancies with BV still reach term.

The important distinction is between an association and a prediction. Studies show that BV is linked with a higher risk of certain complications at the population level. They cannot tell you that your individual pregnancy will have that outcome.

asThere is another reason the guidelines can seem confusing. If BV is associated with preterm birth, you might expect treating every case to prevent premature delivery. But studies of treating asymptomatic BV have not consistently shown that screening and treatment prevent preterm birth. That is why routine screening is not recommended.

If you have symptoms, though, treatment is still recommended.

How is BV treated during pregnancy?

For symptomatic BV, treatment usually involves an antibiotic course prescribed by your OB or another clinician who knows you are pregnant.

CDC-listed options include:

Your provider may choose one treatment over another based on your symptoms, pregnancy, allergies, previous treatment, and what you can tolerate.

Do not swap between products yourself. The strength and formulation matter, and not every BV product has the same pregnancy safety data.

Which BV medications should you avoid during pregnancy?

Some treatments are not recommended because there is not enough safety information or because available data raise concerns.

Tinidazole: CDC recommends avoiding tinidazole during pregnancy because animal data suggest moderate risk and human safety information is limited.

Metronidazole 1.3% vaginal gel: There is not enough pregnancy safety and efficacy information to recommend it.

Metronidazole 750 mg extended-release tablets: These are not the standard pregnancy BV regimen and do not have enough data for routine use.

Clindamycin 2% vaginal cream: CDC lists this among the products to avoid during pregnancy because of limited pregnancy data.

If you are handed one of these products, do not panic and do not stop a medication that your own doctor prescribed without speaking to them. Call the prescribing clinician or your pharmacist and confirm that the specific product is appropriate for your pregnancy.

Metronidazole during pregnancy: what about the first trimester?

You may have seen warnings online about taking metronidazole during early pregnancy.

The current CDC guidance lists metronidazole as a treatment option for symptomatic BV during pregnancy, including the first trimester. Human studies have not established a link between metronidazole and birth defects.

So there is no general rule saying you have to wait until the second trimester to treat BV.

That said, pregnancy is not the time to use someone else's leftover antibiotics or choose a medication based on a Google search. Your prenatal provider should know what you are taking.

Metronidazole side effects: what is normal?

Metronidazole can cause:

• Nausea
• A metallic taste
• Stomach upset
• Diarrhea
• Headache
• Dark urine

These side effects are usually uncomfortable rather than dangerous.

If nausea is making it difficult to take your doses, call your provider instead of stopping the course. They can tell you whether to continue, change the medication, or adjust how you take it.

Avoid alcohol while taking metronidazole and for the period your prescriber or pharmacist recommends afterward.

Clindamycin is another option, but the formulation matters

Clindamycin can be used during pregnancy when metronidazole is not suitable or is not tolerated. Oral clindamycin is listed by CDC as an alternative treatment at 300 mg twice daily for seven days.

The form matters, though.

Clindamycin vaginal cream is not interchangeable with oral clindamycin, and some vaginal formulations are specifically not recommended during pregnancy because of limited safety data.

Clindamycin side effects: when should you call?

Diarrhea is a common side effect of clindamycin.

Mild diarrhea can happen with antibiotics. Severe, persistent, or bloody diarrhea is different. Call your provider promptly if that happens during treatment or after you finish the medication, because clindamycin can sometimes cause a more serious intestinal infection.

Again, do not simply stop the medication on your own. Tell the clinician who prescribed it what is happening.

Do not treat BV yourself during pregnancy

This is one of the biggest differences between BV in pregnancy and the usual advice you see online.

• Do not use leftover antibiotics.
• Do not borrow your partner's medication.
• Do not start boric acid suppositories because someone online recommended them.
• Do not douche.
• And do not assume probiotics can replace antibiotics if you have symptomatic BV.

Boric acid is not recommended during pregnancy, and probiotics have not been shown to cure BV or prevent pregnancy complications caused by BV.

If cost, nausea, allergies, or another side effect is making you hesitant to take the prescribed antibiotic, tell your OB or prenatal provider. There may be another appropriate option.

When BV symptoms need more than a routine appointment

Most BV symptoms do not require an emergency room. Pregnancy changes that calculation when certain symptoms show up alongside discharge or odor.

Go to the emergency room or seek urgent medical attention now if:

• You have vaginal bleeding during pregnancy.
• You have a sudden gush or continuous leaking of watery fluid from the vagina.
• You have regular, painful contractions before 37 weeks.
• You have a fever or chills with foul-smelling discharge and abdominal or pelvic pain.
• You have severe or worsening pelvic or abdominal pain.
• You feel very unwell, weak, faint, or unusually short of breath.

These symptoms can point to problems such as premature rupture of membranes, preterm labor, or an infection that needs immediate assessment. They should not be written off as "just BV."

Call your OB or prenatal provider soon if:

• You develop a new fishy odor or unusual discharge.
• Your symptoms have not improved after finishing treatment.
• Your symptoms come back after treatment.
• You are unsure whether the discharge you are seeing is normal pregnancy discharge.
• You were given a BV medication and are not sure it is safe during pregnancy.
• You are having side effects that make it difficult to finish the antibiotic.

For pregnancy-related symptoms, your OB or prenatal team is the better first call whenever they are available. An urgent care or telehealth clinician can help with some infections, but they cannot replace prenatal care or perform a pelvic exam, fetal monitoring, or vaginal testing when those are needed.

If you cannot reach your prenatal team and you need help deciding how urgently to seek care, August's $39 online urgent care visit connects you with a US-licensed clinician. Be upfront that you are pregnant and tell them how far along you are. If your symptoms suggest a pregnancy complication, you may be directed to your OB, labor and delivery unit, or an emergency department instead.

The bottom line on BV in pregnancy

Symptomatic BV during pregnancy should be treated. Metronidazole and clindamycin are established treatment options, including during early pregnancy. Tinidazole should be avoided, and not every vaginal BV product is appropriate during pregnancy.

A positive test without symptoms is different. Routine screening has not been shown to prevent preterm birth, so your OB or prenatal provider should decide what to do with an unexpected positive result.

And pregnancy changes the stakes. New discharge or odor usually calls for a conversation with your provider, while bleeding, leaking fluid, early contractions, fever, or significant pelvic pain can require urgent assessment.

If you are pregnant and think you have BV, the safest next step is not a quick prescription. It is making sure the right person knows about your symptoms and your pregnancy.