Brandi Jones MSN-Ed, RN-BC is a board-certified registered nurse who owns Brandi Jones LLC, where she writes health and wellness blogs, articles, and education. She lives with her husband and springer spaniel and enjoys camping and tapping into her creativity in her downtime.

About 25% of pregnant women are diagnosed with bacterial vaginosis (BV). BV is a vaginal infection that occurs when there is an imbalance in the normal, healthy vaginal flora (microorganisms). When this happens, the “bad” bacteria outweigh the “good” bacteria that normally live in the vagina. 

The most common symptoms of bacterial vaginosis are a strong “fishy” smelling discharge and an increased amount of vaginal discharge.

BV is easily treated with antibiotics. However, left untreated in pregnancy, BV can increase your infant’s risk of a premature (early) birth or a low-birth-weight baby.  

This article reviews the symptoms, causes, risk factors, complications, prevention, and treatment of bacterial vaginosis during pregnancy. 

Sometimes BV does not cause symptoms. For some women, symptoms are intermittent, meaning they come and go. When symptoms are present, the most common are:

Less common symptoms of BV include:

To diagnose BV, your healthcare provider will take a medical history and perform a physical exam and a vaginal exam. This is similar to a pelvic exam and Pap smear (the exams you get during routine gynecological wellness checks).  

Three of the following four criteria must be met to diagnose bacterial vaginosis:

Your healthcare provider will also likely test for sexually transmitted infections (STIs) during this appointment.

Healthy vaginas have naturally occurring bacteria called normal flora. The healthy bacteria and vaginal discharge keep the vagina clean and free from infection. 

Bacterial vaginosis occurs when the healthy balance of bacteria in the vagina is disrupted. The “bad” bacteria take over the “good” bacteria. 

While BV is not an STI, it can result from sexual activity.  

The following factors increase your risk of BV:

Due to various reasons, there are more recorded cases of BV in Black and Hispanic populations than in other groups in the United States.

While BV is typically mild, it’s essential to treat it, especially during pregnancy. When left untreated, there are rare but serious complications associated with BV, including:

Even if BV symptoms are mild, it’s essential to seek treatment to prevent complications. During pregnancy, BV is typically treated with one of the following antibiotics:  

Your healthcare provider may prescribe pills to be taken by mouth or a gel or cream inserted intravaginally (in the vagina). Antibiotic treatment for BV is usually prescribed for five to seven days. It’s best to abstain from sexual contact until the end of treatment and your symptoms have resolved. 

Research studies have not found concerns with taking metronidazole or clindamycin while pregnant or breastfeeding. This includes in the first trimester of pregnancy. 

Tinidazole is an antibiotic prescribed for nonpregnant people. It has not been studied in pregnancy. Pregnant people should avoid tinidazole.

Healthcare providers often prefer vaginal cream over pills for people who are breastfeeding whenever possible. This is because the medication does not get distributed throughout the body and breast milk as much as oral medication.

Your healthcare provider may also consider the following to treat BV:

Intimate partners who also are women should see their healthcare provider. This is because BV can spread between female sex partners. Both women typically get the infection, and partners may need treatment even if they don’t have symptoms.  

Male partners typically do not need medical treatment. Most research indicates treating your male partner does not help to prevent your recurrent BV. This may change if further studies show that treatment is helpful.  

Sometimes healthcare providers prescribe both oral and vaginal medications for you to take at the same time. This is especially true if the infection is recurring (comes back). With recurring infections, healthcare providers may increase the medication's dose and duration (time). They may also prescribe a maintenance dose of vaginal cream to prevent it from returning.  

While BV is not an STI, it can be passed during sexual activity. The following decreases your risk of bacterial vaginosis related to sexual activity:  

The following tips can also reduce the risk of bacterial vaginosis:

Bacterial vaginosis (BV) is a vaginal infection that occurs when there is an imbalance in the normal vaginal flora. With BV, the unhealthy bacteria outweigh the healthy bacteria in the vagina. 

The most common symptoms of bacterial vaginosis are a pungent “fishy” smelling discharge and an increase in vaginal discharge.

BV is treated with antibiotics that are safe to take during pregnancy. Untreated BV can increase your risk of a premature birth or a low-birth-weight baby. While BV is not a sexually transmitted infection (STI), it is related to sexual activity. Safer sex practices can help reduce the risk of getting BV.

While bacterial vaginosis is common, having a vaginal infection during pregnancy can be unnerving. Women are often concerned it will harm their unborn babies. Fortunately, BV is easily treated with safe antibiotics during pregnancy and while breastfeeding. If you have any symptoms, call your healthcare provider as early diagnosis and treatment decrease the risk of complications such as premature delivery or low birth weight.   

Yes, it’s important to treat BV during pregnancy. Left untreated, BV can cause complications such as preterm delivery or a low-birth-weight baby. 

Your healthcare provider will talk to you about your symptoms and do a vaginal exam. During the exam, they will take a sample of the vaginal discharge with a long cotton-tipped swab. They may also use a pH strip to test the acidity level of the vaginal fluid. 

While this topic is still controversial in the scientific community, the U.S. Preventive Services Task Force (USPSTF) recommends against screening for bacterial vaginosis for women at low risk for preterm labor. However, your healthcare provider may suggest screening if you have symptoms or are at high risk for preterm birth. 

Centers for Disease Control and Prevention. Std facts - bacterial vaginosis.

Planned Parenthood. What is bacterial vaginosis?

Sim M, Logan S, Goh L. Vaginal discharge: evaluation and management in primary care. Singapore Med J. 2020;61(6):297-301. doi:10.11622/smedj.2020088

Ibrahim A. Comparison of in vitro activity of metronidazole and garlic-based product (tomex®) on trichomonas vaginalis. Parasitol Res. 2013;112(5):2063-2067. doi:10.1007/s00436-013-3367-6

Eunice Kenedy Shriver National Institute of Child Health and Human Development (NIH). How do healthcare providers diagnose bacterial vaginosis (bv)?

Bagnall, P, Rizzolo, D. Bacterial vaginosis: a practical review. J Am Acad Phys Assist. 2017; 30(12):15-21. doi:10.1097/01.JAA.0000526770.60197.fa

Bagnall, P. and Rizzolo, D. Bacterial vaginosis: A practical review. J Am Acad Phys Assist. 2017; 30(12):15-21. doi:10.1097/01.JAA.0000526770.60197.fa

By Brandi Jones, MSN-ED RN-BC Brandi is a nurse and the owner of Brandi Jones LLC. She specializes in health and wellness writing including blogs, articles, and education.

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