BV and Preterm Labor Risk: What Every Pregnant Woman Should Know

When I was expecting my second child, I was overly cautious about every little change in my body—especially when something felt off down there. It turned out I had bacterial vaginosis (BV), a condition I hadn’t even heard of until my midwife brought it up. What startled me wasn’t just the diagnosis, but the possibility that it might contribute to preterm labor. If you’re pregnant and wondering about this connection, you’re not alone. Let’s walk through what BV means during pregnancy, what science says about its link to early delivery, and what you can do about it.

Understanding BV in Pregnancy

Bacterial vaginosis is essentially an imbalance of the natural bacteria in the vagina. While it can affect anyone with a vagina, pregnancy presents a unique set of risks. The body undergoes hormonal and immune shifts that can make it more vulnerable to changes in the vaginal microbiome.

During pregnancy, BV might not always show symptoms—making it easy to miss. But even in its asymptomatic form, research from ncbi.nlm.nih.gov has consistently suggested a correlation between untreated BV and complications like premature birth or low birth weight.

How BV Affects the Pregnancy Environment

The vaginal microbiota plays a protective role during pregnancy. When that ecosystem is disturbed—say, when harmful anaerobic bacteria outnumber protective lactobacilli—it creates a cascade of inflammation. That inflammation may trigger the release of prostaglandins and cytokines, which have been implicated in the onset of labor. In simpler terms, the body gets confused and might think it’s time to deliver—even when it’s not.

Symptoms You Shouldn’t Ignore

Though BV can be silent, these are some signals you might notice:

• Watery, gray or white discharge with a strong fishy odor
• Burning during urination
• Vaginal itching or irritation

If you’re experiencing any of these, especially in the second or early third trimester, it’s worth discussing with your OB-GYN.

How Strong is the Link Between BV and Preterm Labor?

Multiple clinical studies have shown a consistent association between BV and preterm birth—defined as delivery before 37 weeks. A meta-analysis published by cdc.gov reported that women with BV during pregnancy were 1.5 to 2.5 times more likely to experience preterm labor compared to those without the infection.

The mechanism isn’t entirely straightforward. However, researchers believe that the inflammatory response set off by BV bacteria, such as Gardnerella vaginalis, may cause uterine contractions or weaken the fetal membranes. If membranes rupture prematurely (also known as PROM), labor can begin too soon.

Is Screening for BV Standard During Pregnancy?

Interestingly, routine screening for BV isn’t part of most prenatal care protocols—unless you’re considered high-risk due to a history of preterm delivery. This is despite the known link to early labor. Some physicians argue that universal screening may lead to overtreatment, while others believe proactive testing could prevent avoidable outcomes.

If you’ve had a previous preterm birth, there’s a strong case for requesting a BV test early in your pregnancy—even if you feel fine.

While the guidelines can vary by region, I personally wish I had pushed for more information sooner during my pregnancy. Knowing your body and speaking up during prenatal visits can make a real difference.

What Happens If You’re Diagnosed With BV During Pregnancy?

Treatment during pregnancy is typically straightforward and safe. The most commonly prescribed medications include:

1. Metronidazole: Usually taken orally in tablet form. It’s effective and considered safe during pregnancy when prescribed appropriately. Read more about Metronidazole for BV.
2. Clindamycin: This antibiotic can be used orally or as a vaginal cream, depending on the physician’s preference. See details here: Clindamycin for BV.

Most providers opt for a short, 5 to 7-day course of antibiotics. However, completing the full course is essential even if symptoms disappear early.

Monitoring After Treatment

Follow-up is key. Just because symptoms improve doesn’t mean the infection is completely gone. Recurrence is unfortunately common. In fact, up to 30% of women treated for BV during pregnancy may get it again within a few months.

That’s why many specialists recommend additional support like probiotics to maintain a healthier vaginal microbiome post-treatment. Just make sure to check with your doctor before adding any supplements during pregnancy.

Steps You Can Take to Lower Risk

While you can’t eliminate every risk factor, certain habits may reduce your chances of BV-related complications:

• Avoid douching—this disrupts your natural vaginal flora. More on BV and douching myths
• Use condoms during sex to minimize exposure to new bacteria. See safe sex tips to avoid BV
• Wear breathable, cotton underwear to reduce moisture buildup
• Strengthen your immunity with a nutrient-rich diet—visit this guide on BV-friendly foods

For more foundational insights on BV, see our main page: What is Bacterial Vaginosis? and explore our full BV in Pregnancy Guide for related concerns.

Can BV Come Back Again During the Same Pregnancy?

Unfortunately, yes—BV has a frustrating tendency to return, even during the same pregnancy. I experienced this firsthand. After my initial round of antibiotics, my symptoms disappeared, but by the beginning of the third trimester, that all-too-familiar odor and discharge were back.

This recurrence doesn’t mean the treatment failed; it’s often related to persistent imbalance in the vaginal microbiome. That’s why it’s crucial to maintain close communication with your provider. They may suggest a second course of antibiotics, alternative therapies, or supportive options like yogurt-based treatments and coconut oil—though these should always be cleared by a doctor first.

Can Recurring BV Increase the Risk of Preterm Labor?

The short answer is yes. Recurring or chronic BV can contribute to sustained inflammation in the cervicovaginal environment. Some studies cited by marchofdimes.org indicate that multiple episodes of BV increase the likelihood of adverse outcomes more than a single episode does.

If you’ve had recurring BV before pregnancy or during it, proactive management becomes even more essential. A collaborative plan involving your OB-GYN and possibly a maternal-fetal medicine specialist can make all the difference.

Supportive Strategies to Reduce BV Flare-Ups

Along with prescribed treatment, several lifestyle changes may help prevent BV flare-ups during pregnancy. Some of these I personally followed after my recurrence, and I genuinely believe they helped:

• Limit sugar intake: High-sugar diets can feed pathogenic bacteria. Learn more about this connection here.
• Opt for pH-friendly hygiene: Use mild, fragrance-free cleansers and skip the overly marketed “feminine washes.”
• Stay hydrated and nourished: Fluids and a balanced diet support your immune system’s natural defenses.
• Reduce stress: While it’s easier said than done during pregnancy, there’s growing interest in how stress might disrupt microbiome balance. Related info here: Can stress cause BV?

Other helpful reads to reinforce your plan include underwear hygiene tips and long-term BV solutions.

BV and Its Relationship with Other Infections

One confusing aspect for many pregnant women—including myself—is distinguishing BV from yeast infections. Sometimes, you can even have both at once. The overlapping symptoms can make it hard to know what’s going on without testing.

If you’re unsure, check out our detailed comparison:
Can I have BV and yeast at once?
and
how accurate are home tests for BV.

BV also increases susceptibility to other infections—especially sexually transmitted infections. Protecting your vaginal health becomes a priority not just for comfort, but also for the safety of your pregnancy.

When to Seek Medical Help Immediately

While some discomfort can be expected in pregnancy, BV symptoms paired with any of the following warrant prompt attention:

• Unusual fluid leakage (possibly indicating amniotic fluid)
• Lower abdominal cramps or tightening before 37 weeks
• Burning sensation accompanied by fever
• Foul-smelling discharge that suddenly worsens

If something feels off, don’t second-guess it. A quick swab at your doctor’s office can rule out infections or catch them early.

To understand all diagnostic options available, visit our guide on how BV is diagnosed.

Wrapping Up: What Helped Me Navigate BV and Pregnancy

Looking back, the most valuable thing I did was ask questions and trust my instincts. I learned that BV is not a moral failing or hygiene issue—it’s a medical condition influenced by multiple factors, many of which are out of our control. But that doesn’t mean we’re powerless.

Getting educated on BV was empowering. I leaned into evidence-based care, stayed in tune with my body, and sought second opinions when needed. By the time I reached week 38, I had no signs of infection—and I delivered a healthy baby boy, right on time.

If you’re navigating this now, know you’re not alone. For a comprehensive overview, start with our main BV resource, and explore related topics in the BV in Pregnancy Guide. From treatment options to dietary support, we’ve built a resource center grounded in medical insight and lived experiences like yours and mine.