Your wardrobe may be working against your fertility

Nadia Shaw

Most people looking to protect or improve their fertility think first about diet, sleep, stress and medical care. Clothing rarely makes the list. But some researchers  say the fabrics people wear (particularly tight, heat-trapping synthetic materials) may be  several environmental factors worth considering.

Polyester, nylon, rayon, spandex and other synthetic blends are common in leggings, seamless underwear, shapewear, gym clothes and wrinkle-resistant garments.

But many are made from petroleum-based materials and may contain dyes, plasticizers, finishing treatments and other chemicals of concern, including some phthalates.

The evidence is more nuanced than the claim that clothing alone causes infertility.

Fertility is influenced by age, genetics, underlying health conditions, smoking, alcohol use, body weight, environmental exposures and many other factors. Still, reducing unnecessary exposure to heat and certain chemicals can be a reasonable part of an  approach to reproductive health.

Tight clothing can matter most for men because sperm production works best when the testicles remain slightly cooler than core body temperature.  Research has linked increased scrotal temperature with poorer sperm parameters, including reduced sperm count and motility.

Heat exposure from sources such as saunas, laptops placed  on the lap and prolonged sitting may also contribute.

For women, tight, non-breathable clothing is  commonly associated with comfort and skin concerns than with proven infertility.

Tight, non-breathable clothing can hold moisture and heat around the groin area,  contributing to irritation or changes in the local environment that may increase the likelihood of yeast infections or  discomfort. Those issues do not necessarily cause infertility, but they can be disruptive for women’s health.

With synthetic materials, chemical exposure is  concern, although it is difficult to measure how much comes specifically from the clothing.

Phthalates, for example, are a  group of chemicals used in plastics and consumer products. In the Journal of Obstetrics and Gynecology, some studies have linked higher  phthalate exposure with changes in reproductive hormones and poorer reproductive outcomes. But exposure also comes from food packaging, cosmetics, household dust and many other  sources, making it hard to isolate the role of a  pair of leggings or underwear.

What is clear is that skin is not an impenetrable barrier. Heat, sweat and friction can affect how the body interacts with substances on the skin’s surface. That does not mean every synthetic garment is dangerous, but it does support a practical, lower-exposure approach — especially for clothes worn tightly and for long periods.

For everyday wear, breathable natural fibers such as cotton, linen, silk and wool can be useful alternatives. Cotton underwear, in particular, is often recommended for comfort and airflow.

People trying to conceive may also want to avoid wearing  tight shapewear, compression garments or synthetic activewear for prolonged periods, especially overnight or during long, hot days.

And if fertility is a concern, speak with a reproductive-health specialist rather than relying on any one lifestyle change as an answer.

This is not a call to throw away every polyester shirt or workout set. It is about paying attention to what stays in close contact with the body for hours at a time.

Fertility is not determined by a single food, product or fabric. It reflects a much larger picture: the environment people create around their bodies, how they sleep, and the medical care they receive. Clothing is only one part of that picture, but it may be a practical place to start.