If you’ve ever had a yeast infection, there’s a good chance you knew something was wrong down there right away. The intense itching, redness and discharge are impossible-to-ignore signs of this uncomfortable — and common — condition. In fact, 75% women will get a yeast infection at some point in their life, and almost half of all women will have 2 or more, according to the U.S. Department of Health & Human Services Office of Women’s Health.

There’s also a good chance you’ve heard that antibiotics are to blame for this pesky problem, and it’s true that one-quarter to one-third of women are prone to yeast infections during or after taking antibiotics. But it’s not the only cause, says Maureen Whelihan, MD, a gynecologist in Palm Beach County, Florida, and a spokesperson for the American College of Obstetricians and Gynecologists.

“Yeast and bacteria live in the vagina in harmony, with the good bacteria eating the yeast to keep it in check,” she says. “Antibiotics often clear out that good bacteria, which prompts the yeast to grow out of control. But they’re not the only thing that disrupts this bacteria-yeast balance.”

Here are several other sneaky causes that could be to blame:

Consuming too much sugar. When Dr. Whelihan tells her patients that Halloween and Easter are the biggest times of the year for yeast infections, they tend to chuckle. But she’s not joking. That’s because eating too much sugar can prompt an overgrowth of yeast, she says.

“When you eat too much sugar, your body tries to get rid of the excess in your urine,” she says. “When that sugar-filled urine passes through you, it creates an environment where yeast have plenty to feed on — yeast love sugar — and the yeast grows out of control.”

The resulting imbalance between the bacteria and yeast in your vagina can lead to a yeast infection.

Uncontrolled diabetes. If you have diabetes, you know it’s important to manage your blood glucose levels. This is especially true if you’re a woman and want to keep yeast infections at bay, says Mary Jane Minkin, MD, clinical professor of obstetrics, gynecology and reproductive sciences at Yale School of Medicine in New Haven, Connecticut.

“Uncontrolled diabetes is more likely to raise your blood sugar, causing yeast to go wild when your body tries to excrete all of that excess sugar,” Dr. Minkin says. Keep in mind, though, that certain diabetes medications work by helping you excrete sugar through your urine, which can also cause yeast infections, she adds. “It’s important to know that you can end up with yeast infections related to your diabetes medication,” she says. If you suspect this may be happening, talk to your doctor about trying a different drug.

Looking for help saving money on yeast infection treatment? Download the Optum Perks app, type in the name of your prescription, and show the coupon at the pharmacy counter.

Hormonal changes. While a woman’s hormones are almost always in flux, a spike in estrogen tends to feed vaginal yeast because estrogen controls glucose levels, says Dr. Minkin. “This is why pregnancy tends to cause yeast infections,” she says. “When you’re in a hyper-estrogenic state, you are more likely to have higher blood sugar levels, and sugar is what makes yeast happiest.”

Also, gestational diabetes is much more common now than it was 20 years ago, and you can see why many pregnant women get yeast infections, says Dr. Minkin. Taking oral contraceptives or undergoing hormone replacement therapy can also cause similar vaginal yeast issues.

Impaired immune system. If you’re experiencing 3 or 4 yeast infections a year and your blood sugar is normal, there’s a good chance your doctor will check for an immune deficiency, says Dr. Minkin. That’s because when your defenses are down, you’re less able to naturally fight off an overgrowth of yeast, she explains. That is also why medications that compromise your immune system, such as steroids and chemotherapy, can make you more susceptible to yeast infections.

One last thought

Some people may blame scented feminine products or wearing panty liners every day for yeast infections, but there’s not a lot of evidence to back this up, says Dr. Whelihan. Instead, the irritation that can result is more likely a case of contact dermatitis, which is generally less itchy and red than yeast, she says. But because these products can be irritating even when you’re not dealing with a yeast infection, it’s best to stick with fragrance-free options instead.

Now that you know the potential causes of yeast infections, get up to speed on treatments like clotrimazole.