What’s a yeast infection?

Vulvovaginal candidiasis, or moniliasis, is a yeast infection of the vulva and vagina. Yeast is a type of fungus. The yeast that most often causes these infections is Candida albicans, but other types of yeast — including Candida glabrata and Candida tropicalis — can also be responsible.

About three out of every four women will have at least one yeast infection in their lifetime, according to American Family Physician. Up to 45 percent will get two or more infections.

During pregnancy, Candida (and the infections it causes) is even more common. According to one study, about 20 percent of women have Candida yeast in their vagina normally. That number goes up to 30 percent during pregnancy. Yeast is more likely to cause infection during pregnancy due to hormone fluctuations.

Because you can pass the yeast to your baby during delivery, it’s important to get treated.

What causes candidiasis?

Candidiasis occurs when the normal number of fungi that reside in the vagina increases enough to cause symptoms. The most common factors that make a woman more likely to get yeast infections include:

During pregnancy, shifting hormone levels change the pH balance in the vagina. This creates an environment that’s more favorable for yeast to grow.

What complications are associated with yeast infections?

In nonpregnant women who have a normal immune system, yeast infections rarely lead to serious complications.

Even in pregnancy, yeast infections don’t usually cause harmful effects in the mother. However, you can pass the yeast to your baby during delivery.

Most babies who develop a yeast infection have it just in their mouths or diaper area. However, though rare, a yeast infection in babies can become very serious, because their immune systems aren’t yet well-developed. It can spread through the infant’s body and affect breathing and heart rhythm, for example. This happens most often in babies who have other things affecting their immune systems, such as prematurity or an underlying infection.

Yeast infections can also cause body-wide infections and serious complications in women who have a weakened immune system because of conditions such as HIV.

What are the signs and symptoms of candidiasis?

With candidiasis, you’ll most likely have itching in your vagina and vulva. You may also notice a white vaginal discharge. This discharge may look similar to cottage cheese and shouldn’t have an odor.

Other symptoms include:

These symptoms may last for a few hours, days, or weeks.

In newborn babies and in women who have a weakened immune system, candidiasis may occur in the mouth. This condition is known as thrush.

Other conditions can cause symptoms similar to a yeast infection, including:

How can I prevent a yeast infection?

You can reduce your risk of future yeast infections by:

  • keeping the vaginal area dry
  • avoiding bubble baths, feminine hygiene sprays, and douches
  • wearing cotton underwear

Although candidiasis isn’t an STD, oral sex may make your condition worse and affect your sexual partner.

How is candidiasis diagnosed?

Your doctor will ask about your symptoms and do a physical exam. To confirm the diagnosis, your doctor will use a cotton swab to take a sample of the vaginal discharge. The sample will be checked under a microscope for signs of the yeasts that cause infections.

In certain cases, your doctor may want to culture or grow in a lab a sample of your vaginal discharge. Cultures help them rule out other types of yeast, such as C. glabrata and C. tropicalis.

How is candidiasis treated?

Most of the time, vulvovaginal candidiasis is easy to treat with an antifungal cream or suppository. The medicine should relieve your symptoms within seven days. However, during pregnancy, you should see your doctor before starting treatment. They can confirm that you actually have a yeast infection and ensure you get a treatment that’s safe to use during pregnancy.

Both oral and topical antifungal drugs are used to treat yeast infections in nonpregnant women. However, oral drugs may not be safe to use during pregnancy. A 2016 study in JAMA found an association between higher risk of miscarriage and oral fluconazole (Diflucan) use during pregnancy. Oral antifungal drugs have also been linked to birth defects.

Topical antifungal drugs that are safe to use during pregnancy include:

clotrimazole (Gyne-Lotrimin)1% cream, 5 grams (g), once a day for 7 to 14 days
miconazole (Monistat)2% cream, 5 g, once a day for 7 days
terconazole (Terazol)0.4% cream, 5 g, once a day for 7 days

How should repeat yeast infections be treated?

During pregnancy, you’re more likely to have repeated yeast infections. Four or more yeast infections in one year is called recurrent vulvovaginal candidiasis.

If you keep getting yeast infections, talk to your doctor. You may need to be evaluated for risk factors such as diabetes or an immune disorder. If pregnancy is the cause, the infections should stop after you deliver.

Research finds that taking an oral “azole” drug for six months reduces your chance of a repeat infection. However, oral antifungal medicines might not be safe to use during your pregnancy. You may have to wait until after you deliver to go on this treatment.