Causes and Risk Factors of Yeast Infection

Candida is the organism responsible for yeast infections, but it usually lives in the vagina in balance with bacteria without causing any problems. Changes to vaginal acidity and the balance of organisms can occur due to antibiotics, diabetes, pregnancy, hormonal therapy, contraceptives, or an impaired immune system. When that happens, Candida cells can multiply unchecked, resulting in a yeast infection.

vaginal yeast infection causes
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Common Causes

Yeast infections have several causes, and some individuals may have more than one at play when an infection strikes.

Antibiotic Treatment

This is a common reason for a yeast infection. The lactobacilli normally found in the vagina produce substances and a level of acidity that inhibits yeast. Antibiotics kill some of this friendly bacteria, which allows yeast to overgrow.

Increased Estrogen

Having an increased estrogen level raises your risk of a vaginal yeast infection. Pregnant women, those taking high-dose estrogen birth control pills, and women on hormonal replacement therapy are at a higher risk than others.


If your immune system is impaired due to corticosteroid medication, cancer treatment, HIV infection, or other causes, you will be at a greater risk of yeast infections.


You're especially susceptible to vaginal yeast infections if you have diabetes. Yeast cells that normally live in the vagina are kept in careful check by the minimally available nutrients in the acidic environment of the vagina. However, in women and girls with diabetes, vaginal secretions contain more glucose due to higher amounts of glucose in the blood. Yeast cells are nourished by this excess glucose, causing them to multiply and become a yeast infection.

High blood sugar also interferes with immune functions that help prevent yeast infections. Those in women with diabetes can indicate that blood glucose levels are not well-controlled or that an infection is brewing in another part of the body.

The presence of yeast itself also blocks the body’s natural defense mechanisms against other infections, increasing the risk of them in people with diabetes. Any infection in a person with diabetes poses a risk because blood sugars may be much higher or lower than normal while the body tries to fight back.

If you experience four or more yeast infections per year, ask your healthcare provider to make sure that your diabetes is being adequately managed.

Cancer Treatment

Vaginal yeast infection is often seen as a side effect of cancer treatment. Your white blood cells, which normally keep the yeast usually found in your vagina and digestive tract from overgrowing, can be reduced by chemotherapy and radiation treatment. Steroid drugs can also reduce your immune system's ability to maintain balance. High-dose antibiotics sometimes used in cancer treatment can also give way to a yeast infection.

Sexual Activity

Yeast infections occur without sexual activity and, therefore, are not considered sexually transmitted infections (STIs). However, yeast can be transferred between sexual partners through vaginal, oral, or anal sex. You can use a condom or dental dam to protect against this. If your sexual activity irritates the vagina, it can disrupt the normal balance and encourage an overgrowth of yeast.

Male sex partners of a woman who has a yeast infection may get a yeast rash on the tip of the penis. A man is more at risk if he has diabetes. A doctor's evaluation and treatment are necessary.

Lifestyle Risk Factors

You can change habits or practices that increase your risk of vaginal yeast infection. Follow these tips to reduce heat, moisture, irritation, and other risk factors.

  • What you wear can make a difference. Underwear with a cotton crotch, rather than one made from synthetic fabric, is recommended. Skirts and pants that are loose-fitting can help keep you cooler and drier. Avoid wearing tight pantyhose and any pants that are tight in the crotch. Change out of wet or damp clothes as soon as possible, including swimsuits and exercise clothing.
  • Change your tampon, menstrual pad, or panty liner frequently.
  • Don't douche, as this will flush out beneficial bacteria and change the acidity of your vagina.
  • Wipe from front to back after a bowel movement so you don't transfer yeast from a stool.
  • Scented feminine hygiene products, bath products, and sprays can irritate the vaginal area and it is wise to avoid them.
  • Use a vaginal lubricant during sexual intercourse to help prevent irritation. You may also want to use a condom or dental dam to prevent transferring yeast between yourself and your partner.
  • Avoid very hot baths and hot tubs.
  • If you have diabetes, work on maintaining good blood sugar control.

When being treated for a yeast infection, especially if you have diabetes, take the full amount of medication recommended by your healthcare provider. If you stop the medication early because you feel better or the symptoms are gone, the infection can return and be even stronger than before.

Frequently Asked Questions

  • What causes a yeast infection?

    Yeast infections are caused by a fungus called Candida. The type that accounts for the vast majority of yeast infections is Candida albicans (C. albicans). Less common types include C. parapsilosis, C. dubliniensis, and C. auris, which are more commonly seen in immunocompromised people with severe systemic infections.

  • What are the risk factors for yeast infections?

    Candida albicans normally lives in the body without causing problems, but it can suddenly overgrow when the immune system is weakened or the vaginal environment is altered. Risk factors include:

    • Antibiotic use
    • Chemotherapy
    • HIV infection
    • Hormonal birth control
    • Poorly controlled diabetes
    • Pregnancy
  • Can you get yeast infections through sex?

    Yes, it is possible. A yeast infection is not considered a sexually transmitted disease, but it is possible to get it from a partner who, say, has a penile yeast infection or oral thrush. Using condoms or a dental dam during sex can help reduce the risk.

  • Can poor hygiene cause a yeast infection?

    On its own, genital hygiene is not considered a risk factor for a yeast infection. However, poor personal hygiene paired with a high frequency of sexual intercourse increases the likelihood that the fungus will be passed from one sexual partner to the next.

  • What are the risk factors for a penile yeast infection?

    An uncircumcised penis is one of the major risk factors. This is because the moist environment beneath the foreskin promotes the growth of the Candida fungus. Poor penile hygiene and obesity further increase the risk.

7 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Rodrigues CF, Rodrigues ME, Henriques M. Candida sp. Infections in Patients with Diabetes Mellitus. J Clin Med. 2019;8(1):76. doi:10.3390/jcm8010076

  3. Centers for Disease Control and Prevention. Cancer Patients and Fungal Infections.

  4. U.S. Department of Health & Human Services/Office on Women's Health. Vaginal yeast infections.

  5. Turner SA, Butler G. The candida pathogenic species complex. Cold Spring Harbor Perspec Med. 2014;4(9):a019778. doi:10.1101/cshperspect.a019778

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By Heather M. Ross
Heather M. Ross, PhD, DNP, FAANP is a nurse practitioner and PhD in Human and Social Dimensions of Science and Technology.