Can You Take Metronidazole While Pregnant?

Metronidazole is the first-line treatment recommended for bacterial vaginosis (BV), a condition that can cause symptoms like itching, discharge, and odour in women. It is a type of antibiotic that works by killing the bacteria causing BV and inhibiting their growth..

Any woman can get BV, and up to 49% of pregnant women globally are affected, so getting safe and appropriate treatment is important. But can you take metronidazole while pregnant? Let's explore the evidence from various sources.

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The Effect of Metronidazole During Pregnancy

Metronidazole, a medication commonly used to treat infections, was found to interfere with foetal development and promote changes in placental structure during pregnancy in some early animal studies. However, these findings were inconsistent and difficult to replicate in later research.

When it comes to its effects on humans, particularly during pregnancy, the available data does not suggest an increased risk of congenital malformations, preterm delivery, low infant birth weight, intrauterine death, or complications for newborns following exposure to the drug during pregnancy.

A 2015 study found that there was no association between taking metronidazole treatment and preterm birth, low birth weight, or congenital abnormalities if treatment was received during the first trimester in humans. 

Is Metronidazole Safe in Pregnancy?

The decision to use the drug should be based on a careful assessment of the benefits and risks between you, your doctor, and your obstetrician. If you have BV symptoms while pregnant, reducing your exposure to common risk factors can help, and you may be prescribed oral metronidazole tablets.

NICE guidelines state that metronidazole can be used in pregnancy if the benefits outweigh the risks. High-dose regimens, however, should be avoided; these include a single 2 g dose. Instead, you may be offered 400 mg twice a day for 5 to 7 days.

Some of the things you can do to lower your risk of bacterial vaginosis during pregnancy include avoiding:

• smoking
• vaginal douching
• using antiseptics, bubble baths, or perfumed shampoos and soaps in the bath or shower

Effect of Metronidazole on Preterm Birth Delivery

Treating bacterial vaginosis with metronidazole during pregnancy is effective and offers no teratogen risk or the ability to cause abnormal foetal development, birth defects, or congenital abnormalities. Treating BV with metronidazole can reduce preterm births in people who have had a premature baby previously by 18% compared to 39% in people who did not receive metronidazole.

A further review found that metronidazole use during pregnancy was not only effective at clearing bacterial vaginosis but also reduced preterm births when used in combination with other antibiotics.

Metronidazole and Breastfeeding Considerations

According to the NHS, metronidazole is okay for use if you are breastfeeding, but it should only be taken for a short time. You will also need to monitor your baby while taking metronidazole to ensure it is not affecting your baby's usual feeding pattern. If you have any concerns, you should speak to your clinician for more advice.

According to healthcare guidelines, oral metronidazole:

• Can be taken while breastfeeding.
• May make your breast milk taste metallic, but it is unlikely to cause side effects in the baby
• Is best if it is taken only for a short time

If you are prescribed metronidazole cream or gel, you may be able to use it for longer because it is unlikely to pass into your breast milk. However, it is important that your baby does not come into contact with the areas of your body where the cream has been applied. You should also ensure that you wash your hands after handling metronidazole cream or gel before touching or picking up your baby.

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Does Metronidazole Affect Fertility? 

There's no clear evidence to suggest that taking metronidazole reduces fertility in either men or women. Some early animal studies have shown that high doses of metronidazole can result in lower sperm counts in male rats, although these effects are partially reversible. However, these effects have not been seen strongly in human studies.  

Interestingly, some research suggests that BV could affect a woman’s reproductive health and contribute to the development of conditions like pelvic inflammatory disease (PID), which can cause infertility. Therefore, seeking urgent treatment for BV symptoms can prevent further complications that may affect your fertility. 

Final Thoughts About Metronidazole in Pregnancy

Metronidazole can be used for bacterial vaginosis during pregnancy, but caution is advised, especially during the first trimester. The decision to prescribe this medication should be based on a thorough evaluation of the individual case, taking into account the type of infection, the stage of pregnancy, and the potential risks and benefits.

Exposure to Metronidazole at any stage in pregnancy would not usually be regarded as grounds for termination or additional fetal monitoring, but clinicians must consider all risk factors when performing case-specific assessments. It is also safe for use during breastfeeding, with some considerations. Always consult with a healthcare provider for personalised recommendations.

Get Help With Bacterial Vaginosis From Prescription Doctor

Oral metronidazole tablets are safe and effective during pregnancy, and are the first-line treatment recommended by NICE for symptomatic bacterial vaginosis. However, if you are concerned about taking antibiotics or getting BV treatment while pregnant or breastfeeding, you should speak to your clinician for further advice.

At Prescription Doctor, we understand that BV symptoms can be uncomfortable, and getting to see your GP isn’t always possible. That’s where we come in. Since 2013, we have been helping people like you access the treatments and advice they need to take full control of their health. Our GPhC-registered pharmacy can dispatch your medications, following approval from our registered clinician, in plain, unmarked packaging, providing you with a confidential and trusted service.

If you need access to bacterial vaginosis treatment, start an online consultation today. 

Authored By

Leanne Edermaniger

Medical Content Writer

Leanne is a science and health content writer focusing on human health and biology while utilising her solid academic background.

Published on: 11/08/2023 Re-Published on: 17/09/2025

Reviewed By

Mohamed Imran Lakhi

MPharm - Lead Pharmacist

Imran Lakhi is the superintendent pharmacist and founder at Prescription Doctor. He has been at the core of our team.

Reviewed on: 17/09/2025