Cotton underwear, once the fabric of choice for panties, is disappearing from shelves and that has some gynecologists concerned.

For hundreds of years, cotton was extolled for its health benefits.

Lynn Sorge-English, an associate professor at Dalhousie University's costume studies program, said the cotton brief overtook knickers by the mid-20th century. Then cuts and sizes gradually shrunk, from thigh length to thong sized and a sea of blends were introduced.

For those concerned with women's health, that's an issue.

"I recommend 100 per cent cotton underwear because it's breathable," said Dr. Lianne Yoshida

"The airflow will help keep moisture away and help keep the balance of everything appropriate.”

Not only can good airflow help prevent infections, Yoshida said it can help clear them up more quickly.

Hi-tech underwear

Heading into most underwear stores, 100 per cent cotton underwear looks like a thing of the past. While packages of bulk cotton underwear are still available at Wal-Mart and other big box stores, fun underwear in a slightly less severe cut is harder to come by.

The CBC's Polly Leger asked some of her friends to open their drawers so she could peek at their drawers.

Click below to hear what she found:

For mobile users: click here.

She said her friends' underwear is made up of synthetic fabrics such as nylon, modal or cotton-spandex blends. While big brand names like LaSenza do have cotton on offer, it's a 95 per cent cotton, five per cent spandex blend.

Cotton also isn't known for its sex appeal. For the women Leger talked to, it brings to mind "granny panties."

Listen to their memories of cotton underwear:

For mobile users: click here.

While exact point when synthetic fabrics overthrew cotton is unclear, Sorge-English narrows it down to the 1980s when exercise and stretchy fabrics were trendy.

"Gym wear really became an extension of their bodies and that then moved through to undergarments, which also became an extension of their bodies. If you want to have an extension of your body, cotton really wouldn't do it, because cotton has a way of stretching and going out of shape quickly, and it's not really at one with the body,” she said.

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How concerned are you about the materials in your underwear drawers? (CBC)

Some high-end retailers still carry luxury cotton underwear. Mills Brothers in Halifax carries two brands of 100 per cent cotton undergarments. One brand, Knock Out! Smart Panties,  begins at $30 a pair, while the other, Hanro, sells for $58.

Doctor recommended

Yoshia said most well-respected organizations, like the Society of Obstetricians and Gynaecologists of Canada and its American counterpart all mention the virtues of cotton underwear.

But when she looked in the medical books, she only found two published scientific studies looking at the issue.

"One found no sign of increased infection in women who wore synthetic underwear." said Yoshida. "Another study showed sort of the opposite. They said there was an increased risk of an infection in women who wore pantyhose."

Despite the few scientific studies looking at the effect of cotton underwear, Yoshia said ultimately, the conventional wisdom is what she'll stick with.

"I think I'll still recommend 100 per cent cotton underwear because there's no downside to that."