Birth control is a common part of many people's lives, helping to prevent unwanted pregnancies and, in some cases, manage other reproductive health conditions. However, a question that often arises is whether birth control can cause bacterial vaginosis (BV).

Keep reading to learn more about how some forms of birth control can influence the risk of developing bacterial vaginosis.

Hormonal vs non-hormonal birth control

Birth control, also known as contraception, refers to any method, medication, or device used to prevent pregnancy. Some methods involve the use of synthetic versions of hormones such as estrogen and progesterone, while others are non-hormonal. It’s important to make this distinction because different contraceptive methods can affect your vaginal health in different ways.

Hormonal contraception includes options like:

  • Birth control pills (the mini pill and combined oral contraceptive pill)
  • Contraceptive patch
  • Shot (Depo-Provera)
  • Vaginal ring
  • Implant
  • Hormonal intrauterine device (IUD).

These methods release hormones, usually a combination of estrogen and progestin or progestin alone, to prevent ovulation, thicken cervical mucus, and thin the uterine lining, making it difficult for sperm to reach an egg.

Non-hormonal birth control methods don’t use hormones to prevent pregnancy (as the name would suggest). They include:

  • Copper IUDs
  • Male and female condoms
  • Diaphragms
  • Cervical caps
  • Spermicides
  • fertility awareness methods (FAM).

Copper IUDs, for example, release copper ions that are toxic to sperm, preventing fertilization. Condoms, diaphragms, and cervical caps create a physical barrier that stops sperm from traveling up into the uterus and fallopian tubes. Meanwhile, FAM involves tracking your cycle and avoiding unprotected sex on days when you’re most fertile.

What is BV?

Bacterial vaginosis (BV) is a common vaginal infection caused by an imbalance of the bacteria normally present in the vagina (known as vaginal dysbiosis). Normally, “good” bacteria, chiefly Lactobacillus species, produce lactic acid that helps maintain the vagina’s acidic pH and prevent harmful bacteria from taking over.

In bacterial vaginosis, these good bacteria are outnumbered by “bad” bacteria, leading to symptoms such as a thin, grayish-white vaginal discharge with a fishy odor, itching, and burning during urination. Some women, however, might not experience any symptoms at all.

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Can birth control cause BV?

Different forms of birth control can impact the risk of developing bacterial vaginosis in various ways. This impact is particularly significant in women of reproductive age, as hormonal changes can influence the vaginal microbiome.

Hormonal birth control 

Research suggests that hormonal contraceptive use may actually lower the risk of bacterial vaginosis. The hormones in these contraceptives help keep the vaginal microbiome stable, reducing the chances of bacterial imbalances.

Studies have shown that hormones, especially estrogen, play a big role in vaginal health by promoting the growth of Lactobacilli. When estrogen levels are low, it’s easier for bad bacteria to disrupt the normal flora in the vaginal microbiome.

A systematic review found that using combined oral contraceptives may lead to a balanced microbiome and a lower frequency of bacterial vaginosis. That’s because the hormones in these contraceptives, especially estrogen, promote stability in the vaginal microbiome by affecting glycogen, which is a food source and key factor for the growth of beneficial Lactobacilli bacteria.

Another study looked into the effects of various birth control methods on bacterial vaginosis. The researchers followed 3,077 women over a year and found that those using birth control pills, hormonal injections, or implants were much less likely to develop bacterial vaginosis compared to those using non-hormonal contraception.

Non-hormonal birth control and vaginal microbiome

Now for the not-so-great news. There seems to be an association between BV and non-hormonal methods. These methods can also cause vaginal irritation, which may further disrupt the natural balance of bacteria in the vagina.

Spermicides, or condoms with spermicidal lubricants, may increase the risk of bacterial vaginosis. Spermicides can disrupt the natural balance of bacteria in the vagina, creating an environment conducive to the overgrowth of BV-causing bacteria.

Some research also shows that women with copper IUDs may have higher rates of bacterial vaginosis. A study published in 2020 found that bacterial vaginosis was more likely to occur in people using copper IUDs compared to those using hormonal IUDs. Other studies since then have had similar findings.

It seems like the copper IUD could influence the vaginal microbiome and create unwanted imbalances that lead to bacterial vaginosis, but we need more data since there’s not much compelling evidence.

Risk factors for BV

Besides the type of birth control you’re on, several other factors can influence the risk of developing bacterial vaginosis:

  1. Being sexually active: Bacterial vaginosis isn’t a sexually transmitted infection (STI), but sex can be a trigger. Condom use drastically reduces your risk of developing both STIs and vaginal infections, including bacterial vaginosis.
  2. Multiple sexual partners: Having multiple sexual partners or a new sexual partner can increase the risk of bacterial vaginosis.
  3. Douching: Using vaginal douches disrupts the natural balance of bacteria in the vagina and puts you at increased risk of vaginal infections. Remember, your vagina is a self-cleaning organ!
  4. Smoking: Women who smoke are at an increased risk of developing bacterial vaginosis.
  5. Lack of Lactobacilli: A naturally low level of Lactobacillus bacteria in the vaginal microbiome can predispose women to bacterial vaginosis. Lactobacilli naturally decrease with age, so it’s not uncommon to get bacterial vaginosis during menopause.

It's quite challenging to identify if your birth control is causing recurring bacterial vaginosis infections since the exact cause of bacterial vaginosis is still a bit of a mystery. Plus, if you're on birth control, chances are you're sexually active, which is a risk factor for bacterial vaginosis in and of itself.

While some forms of birth control could influence the risk of developing bacterial vaginosis, it's important to remember that the choice of contraception should be based on individual health needs and preferences. 

Like any medication, birth control is rarely one-size-fits-all. Many different factors go into choosing the right contraception for you. Ask your healthcare provider if combined oral contraceptives with higher estrogen levels may help if you're concerned with BV recurrence.


Is BV a side effect of birth control?

Bacterial vaginosis isn’t a known side effect of birth control. While some forms of hormonal contraception might actually decrease your risk of developing bacterial vaginosis, there is some evidence that non-hormonal birth control could make bacterial vaginosis more likely. That said, everyday behaviors like smoking and having sex are also considered risk factors for bacterial vaginosis, so it’s tricky to pinpoint whether your birth control is to blame for recurrent bacterial vaginosis infections.

Can birth control throw off your vaginal pH balance?

Some forms of birth control might throw off your pH balance. Spermicides and copper IUDs have been shown to shift the vaginal microbiome. Meanwhile, forms of birth control containing estrogen could increase your risk of yeast infections. This doesn’t mean that going on birth control is a surefire way to develop a vaginal infection, though! But if you’re concerned, you should speak to your healthcare provider or OBGYN and discuss your options.

Why am I suddenly getting BV all the time?

If you find that you're experiencing bacterial vaginosis a lot, it could be because of some common everyday habits or factors that can disrupt the natural balance of bacteria in your vagina. Things like having multiple or new sexual partners, using scented soaps or vaginal hygiene products, or smoking can all play a part in this. Even hormonal changes and chronic stress can contribute to bacterial vaginosis. 

Can birth control cause fishy odor?

Some birth control methods could alter your vaginal pH and cause a fishy odor, which might be a sign of bacterial vaginosis. However, a fishy odor could also point to other issues like trichomoniasis or pelvic inflammatory disease. If you notice a fishy odor along with other