What Causes Yeast Infections and How Can I Prevent Them?

Most of us know the signs and symptoms all too well; that incredible “V” itch, inside and out, that just won’t quit; the thick white discharge and the redness, soreness, and sensitivity that screams yeast infection. Candida (yeast), a fungus, is the second most common cause of vaginal symptoms, second only to bacterial vaginosis (BV), and surveys suggest the prevalence is highest among women in their reproductive years.

Candida is considered part of the normal vaginal flora (the natural vaginal ecosystem), but overgrowth can result in infection. Most commonly, Candida infects the vagina from rectal transmission since yeast naturally live in the gastrointestinal (GI) tract. A less likely source is sexual transmission or vaginal overgrowth. Antibiotic use increases the risk of yeast because the normal flora becomes imbalanced. Women taking the pill, estrogen therapy, or who are pregnant are particularly prone to yeast due to increased estrogen levels. Those with poorly controlled diabetes or weakened immune systems are at higher risk too.

And what about sex? While yeast is not a traditional STI, the type of sex may be a factor in affecting yeast levels. Infection may be linked to oral sex, and less commonly to anal. Evidence also suggests certain hygiene practices might be partially to blame including douching and tampon or menstrual pad use. Constricting, non-breathable clothing might also play a role.


The purpose of treatment is to relieve symptoms. Women without bothersome symptoms and sexual partners do not require treatment. 

Here’s the good news! Treatment for an uncomplicated yeast infection is pretty straightforward. Various over the counter (OTC) creams or suppositories are effective, short term (1–7 day courses), safe, and well-tolerated. Alternatively, an oral tablet available by prescription is usually single dose and effective. If you aren’t sure what’s going on down there or infections seem to be chronic or recurrent, you’ll definitely want to see your gyno.

What’s a woman to do to prevent these pesky infections?  For starters, watch what you eat. Diets high in sugar or alcohol might increase risk. Hygiene products laden with chemicals or which are heavily fragrant can be irritating and prompt symptoms. Lubricants with glycerin have been linked to yeast infection; avoid these. Let the V breathe! Avoid 24/7 pantiliner, pad and tampon use. Try less restrictive, more breathable panties or undergarments and aim for a cotton crotch. Wear loose, comfy garments to sleep. Better yet… go commando from time to time. Get out of wet work out clothes and bathing suits as soon as possible.

Regular probiotic use, be it oral or vaginal, might play a role in yeast prevention, but the jury is still out on this.

For those with constant and recurrent yeast, boric acid vaginal suppositories (yes, the stuff that kills roaches!) can be used weekly as a preventive measure. They work by keeping the vaginal pH acidic. Evidence suggests oral nystatin, an antifungal medication, does not prevent vaginal yeast and lactobacillus (oral or vaginal) does not prevent infection related to antibiotic use. In women susceptible to yeast when taking antibiotics, a dose of fluconazole at the start and end of antibiotic therapy may prevent antibiotic-related infection.

What not to do

Sadly for those who swear by it, topical plain yogurt on the external vulva or even in the vagina might be soothing but is not effective treatment for yeast. Of course, it goes without saying that unsweetened and non-fruit varieties are preferred here if you engage in this DIY remedy. Intravaginal garlic cloves and tree tree oil have no role in yeast prevention or treatment either.  

Have a question for Dr. Dweck? Leave it in the comments!

Featured image by Tiffany Sutton

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Author Bio Alyssa Dweck MS MD FACOG is a gynecologist in Westchester County, NY. She is proficient in gynecologic surgery and has expertise in female sexual health. She has been voted Top Doctor in New York Magazine and Westchester Magazine. She provides care to women of all ages and has delivered thousands of babies. A graduate of Barnard College, she has a Masters Degree in Human Nutrition from Columbia University and her MD from Drexel University in Philadelphia. She did her residency training at Lankenau Hospital in Wynnewood, Pa. She is an Assistant Clinical Professor in the Department of Obstetrics, Gynecology and Reproductive Science at the Mount Sinai School of Medicine and a Consultant Massachusetts General Hospital (Vincent’s Memorial Ob/Gyn Service). Dr. Dweck is on the Health Advisory Board of Family Circle Magazine and has strong media platform. She has been featured on The Today Show and Good Day LA. Dr Dweck has co-authored three books, including the newly released The Complete A to Z of the V. An accomplished triathlete who also enjoys sports cars in her 'spare' time, Dr. Dweck lives in Westchester County, New York, with her husband, their two sons and their English bulldog. For more information, please visit www.drdweck.com.

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