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. 

What Are the Symptoms of Bacterial Vaginosis?

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:

A strong odor: BV often comes with a foul-smelling vaginal discharge. It may be stronger after vaginal sexual intercourse or menstruation. Increased vaginal discharge: BV can also cause an increase in vaginal discharge. It is usually a thin (and sometimes foamy) gray, greenish, yellow, or white.  

Less common symptoms of BV include:

Burning or itching in the vaginaBurning with urinationItching around the outside of the vaginaBleeding after intercourse

What Causes Bacterial Vaginosis?

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

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

A pH above 4. 5 Thin, increased vaginal discharge Fishy odor when 10% potassium solution is added to the discharge sample 20% or greater clue cells (fuzzy-looking cells that indicate bacteria) when the discharge is examined under a microscope

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

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. 

What Are the Possible Complications of Bacterial Vaginosis?

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:

Douching regularly  Using fragranced feminine hygiene products  Having multiple sex partners Not using condoms Smoking Having sex with women (typically, both women get the infection) Pregnancy (due to hormone changes) Having an intrauterine device (IUD) (this is a small risk with limited evidence)

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

Preterm delivery or low birth weight: Having BV during pregnancy increases the risk of having your baby too early. It also increases the risk of the baby having a low birth weight. STIs: BV increases your risk of getting STIs, including human immunodeficiency virus (HIV), herpes simplex virus (HPV), chlamydia, or gonorrhea. Pelvic inflammatory disease (PID): PID is an infection of the uterus, ovaries, and fallopian tubes.   Infertility: Untreated BV can lead to PID, increasing the risk of infertility or less success with fertility treatments. Increased risk of infection after gynecologic surgeries: BV is a risk factor for developing infections after gynecological surgeries such as hysterectomies (surgical removal of the uterus).  

How Is Bacterial Vaginosis Treated During Pregnancy?

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: 

Flagyl (metronidazole) Clindacin, Cleocin, Clindesse (clindamycin)

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. 

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

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.

Probiotics (oral or vaginal) Boric acid  Vaginal vitamin C Xifaxan (rifaximin) Sucrose gel

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. 

How to Prevent Bacterial Vaginosis 

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: 

Use barrier devices such as condoms and dental dams. Limit the number of sexual partners or abstain from sexual activity. Avoid vaginal contact with anything that has touched your anus. Clean sex toys after every use.

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

Avoid fragranced soaps, sprays, or feminine hygiene products. Avoid vaginal douching. Wear breathable underwear made from fabric such as cotton. Wipe from front to back after you use the restroom. Quit smoking.

Summary 

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.

A Word From Verywell

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.