Bacterial vaginosis during pregnancy is both more common and more consequential than outside of pregnancy — roughly 10 to 25 percent of pregnant women develop BV, and it raises the risk of preterm birth by 40 to 50 percent. The good news: safe, effective treatment exists in every trimester. This is what you need to know, and why your OB is the right person to see.
Outside of pregnancy, BV is mostly a quality-of-life issue with some downstream STI and PID risk. In pregnancy, the stakes rise sharply. The anaerobic overgrowth and inflammation that define BV can trigger local cytokine release, weaken fetal membranes, and ascend into the decidua.
NIH-indexed meta-analyses and CDC guidance document several consistent associations:
Symptoms are generally the same as outside of pregnancy:
Pregnancy itself produces increased physiologic vaginal discharge — usually clear to milky, non-malodorous. The odor is the distinguishing feature of BV. Any unusual discharge or odor in pregnancy should prompt a same-day call to your OB or midwife.
The 2021 CDC STI Treatment Guidelines and ACOG guidance are aligned: pregnant patients with symptomatic BV should be treated, regardless of trimester. The safe, first-line options are:
Long-standing first-line regimen. Despite older Category B labeling and historical concern about first-trimester use, multiple large cohort studies indexed on PubMed and referenced in CDC/ACOG guidance show no increased risk of birth defects, and current FDA DailyMed labeling supports use in all trimesters when clinically indicated. The alcohol precaution still applies — no alcohol during treatment and for 3 days after.
Effective alternative when metronidazole isn't tolerated or preferred. Safe across all trimesters.
Also safe in pregnancy. Much less systemic absorption. Good option for patients who had severe GI side effects with oral metronidazole in a prior course.
Several older studies suggested a possible association between vaginal clindamycin cream used after 22 weeks and adverse neonatal outcomes. Although the data are not definitive, most OBs avoid vaginal clindamycin cream in late pregnancy out of caution. Oral clindamycin remains safe throughout.
Drugs like ciprofloxacin and levofloxacin are not first-line for BV in anyone, and they are avoided in pregnancy because of fetal cartilage concerns. These antibiotics have no meaningful role in BV treatment.
Boric acid is potentially toxic to pregnancy and must not be used during pregnancy. It also shouldn't be kept within reach of small children after delivery.
Not effective and potentially harmful in pregnancy. Don't try to self-treat BV with non-prescription options.
This is a nuanced area. Routine BV screening of all pregnant women has not been shown to reduce preterm birth in low-risk pregnancies. However, ACOG and CDC both support treatment of asymptomatic BV in patients with a prior spontaneous preterm birth, given the magnitude of that prior risk. Your OB will decide based on your obstetric history.
CDC guidance recommends retesting 1 month after completion of BV treatment in pregnancy. Recurrence rates are high, and recurrent BV in pregnancy has the same downstream risks as a first episode. Your OB or midwife will arrange the follow-up test.
Some practical, low-risk strategies supported by CDC guidance and general obstetric practice:
There are several reasons Bidwell Health — and most responsible general telehealth services — do not treat pregnant patients for BV or similar conditions:
If you're pregnant and think you have BV, call your OB or midwife today. Most obstetric offices have same-day availability for symptoms like this. If you don't yet have a pregnancy care provider, go to a local OB/GYN clinic, a community health center, or a Federally Qualified Health Center — most accept walk-ins or same-week appointments, and many have sliding-scale fees.
For non-pregnant patients with symptomatic BV in our 12 licensed states (Florida, New York, Virginia, Washington, Arizona, Colorado, Connecticut, Iowa, Maryland, Montana, New Mexico, Utah), a $45 online BV visit with a licensed NP takes about 15 minutes. Prescription sent to your pharmacy the same day.
BV is associated with preterm premature rupture of membranes (PPROM) and preterm labor. The absolute risk increase is modest per individual pregnancy, but large enough that CDC, ACOG, and most OBs treat symptomatic BV promptly in pregnancy.
BV itself doesn't cause congenital infection. The downstream risks — preterm birth, low birth weight, neonatal infection if there is chorioamnionitis — are related to pregnancy complications, not direct transmission.
Yes — metronidazole is considered compatible with breastfeeding per most lactation guidance, though some providers prefer vaginal gel or clindamycin for breastfeeding patients. Discuss with your postpartum or OB provider.
Usually yes, but not always. Other causes include retained tampon, trichomoniasis, and less commonly other infections. Your OB will evaluate with a pelvic exam, pH testing, and wet mount or NAAT testing as needed.