• I traded my nighttime underwire bra for a softer one designed specifically for sleeping.
• The Prettywell Sleep Bra has multiple four and five stars reviews on Amazon. It retails for $22.
• The bra was lightweight and comfortable, so I’m adding more to my pajama drawer.

What sleep habit do Hollywood celebrities Halle Berry, Sarah Jessica Parker, and Marilyn Monroe have in common?

The A-listers wear – or wore – a bra to bed each night. So do I, which is exactly why I set out to learn more about the practice.

There is plenty of advice being passed from woman to woman about bras in bed. In 2014, Berry told Yahoo Sports that her mother taught her: “If I don’t want my boobs to hit my knees by the time I’m 30, I should wear a bra, even to bed.”

A year earlier, Amy Greene, a close friend of Monroe, told the Huffington Post that the star’s idea of pajamas was a “big bra.” Greene likened it to “what we used to wear in a convent.” And Parker supposedly believes so much in bras in bed that she had it written into her contract for her character on “Sex in the City.”

I discussed my nocturnal preference with some girlfriends recently. A few said they felt the same way, while others called it “weird” or “yucky.”

The mixed reactions invited my curiousity of the pros and cons of sleeping in a bra. For me, it’s more out of habit than to prevent ptosis, the scientific term for sagging breasts. Either way, it was worth seeking out more information.

I wear underwire bras to bed that I used to wear during the day, but that may not be the best style for overnight use

My improvised sleep bras are recycled from the underwire ones that I used to wear during the day. They’re universally gray and fraying after repeated manglings in the washing machine and tumble dryer.

I reached out to breast health specialist Dr. Nandini Kulkami, the medical director of surgical oncology for Inspira Medical Group. Kulkami strongly advises against the non-stop use of an underwire.

“The constant pressure of the wire can cause restriction and breast pain,” she told Insider.

But she said she isn’t against a bra in general — it’s the type of bra. A softer version without metal wires or pin straps may help certain people, the doctor explained.

“It can depend on your cup size, body type, and how well you sleep,” Kulkami added. “It really comes down to personal choice.”

She said people should not be concerned about a possible link between breast cancer and the continual use of a bra, a common misconception. In 1995, a husband-and-wife team of “medical anthropologists” hypothesized that the constriction of your standard underwire bra damaged the lymphatic system.

But peer-reviewed medical research has found no connection, Kulkami said.

One study, by The Public Health Sciences Division at Fred Hutchinson Cancer Research Center in Seattle, Washington, analyzed the bra-wearing habits of 1,500 women. Two-thirds of those women had breast cancer.  

At the time of its publication in 2014, researcher Lu Chen explained the findings: “Our study found no evidence that wearing a bra increases a woman’s risk for breast cancer. The risk was similar no matter how many hours per day women wore a bra, whether they wore a bra with an underwire, or at what age they first began wearing a bra.”

A medical doctor said that people with larger breasts are more likely to benefit from a sleep bra

Kulkami shared some typical scenarios in which someone may want to wear a bra to bed.

Breasts can be more tender and achy during your period. “In those circumstances, it might be a good option to get more support from a sleep bra,” she said.

That goes for people with larger breasts too, who may experience pain in the upper back and neck due to the pull of gravity. Kulkami also noted that this type of discomfort was the most common reason for patients to opt into breast reduction surgery. Others may find relief with a sleep bra, she explained. 

I acted on her advice and traded my underwire bra for a product specifically designed for overnight wear.

The Prettywell Sleep Bra is a seamless combination of stretchy fabric and comes with removable pads

The Prettywell Sleep Bra, which is recommended for anyone with a D cup or smaller, is one of the most popular products on the market. More than 70 percent of reviewers on Amazon have given it four or five stars.

One Amazon customer wrote under the reviews that it “feels like you’re wearing nothing.” Another raved that “these are like if clouds were combined with butter and yet somehow supported your boobs.”

I checked the size chart and ordered a medium Prettywell in nude. It retailed for $21.89 at the time of publishing. It’s a seamless bra, and the fabric is a combination of nylon and Spandex.

My bust is relatively full, so I took out the removable pads. Since the bra material is stretchy with no clasps, I pulled it over my head and climbed into bed.

I tried out my new purchase for two weeks. It seemed like the bra was barely there since my rib cage no longer felt compressed. In fact, it was so comfortable, I wondered how on earth I’d put up with an underwire for so long.

Since the material was lightweight, you couldn’t see it under my pajamas either. Plus, it was breathable.

The downside was that I needed more support. The bra was so thin, it would often ride up. I wished I had read the small print in the product description recommending to size up if your chest is “plump.”

My other criticism has to do with laundry. The bra should be washed by hand. If you have a hectic lifestyle like me, I find that hand-washing is impractical. I compromised by putting it in a mesh bag with my regular laundry. 

Wearing the wrong size sleep bra can create problems.

As Kulami suggested, wearing a bra to bed works for some and not for others. If you opt in, check that the size is the best fit.

Dr. Regina Hampton, a board-certified general surgeon who specializes in breast cancer surgery at Doctors Community Hospital near Washington, D.C, told Healthline that buying a well-fitting sleep bra is important.

She explained the right purchase will “prevent things like a fungal infection under the breasts, which can happen if the bra doesn’t tuck under the breast properly, resulting in skin touching skin.”

My biggest mistake with the Prettywell was buying a medium instead of a large. I plan to order the larger size when I add more Prettywell bras to my sleepwear collection. 

The keyword is “when,” not “if.” Aside from the hand-washing advisory – which I don’t have time to follow – these bras are the future for my overnight breast support. My tattered heap of underwire sleep bras is already in the trash.