The 7 things a bra-fitter needs you to know if you're a D+ cup.

It starts with a niggling feeling that something isn’t quite right. Your boobs aren’t sitting right and no matter how many times you do a sneaky little adjust while no one’s watching, they just don’t seem to be cooperating.

By the end of your morning meeting, the wire is digging into your left armpit.

It’s fine, you tell yourself, I’ll just keep that arm slightly raised at all times and make no sudden movements. 

At lunchtime, the chafing begins. It’s subtle at first but by your afternoon cup of tea, you’re seriously considering sticking your hand in the office tub of butter and rubbing it on your skin to try to get some kind of sweet, sweet relief.

By your afternoon commute, it feels like your boobs are on fire. Your back is sore. And you just keep picturing what life was like before you put on that bra and left the house in the morning.

You rush home, fling open the front door, reach under your top, undo the clasp, and throw your bra on the floor.

Ahhhhhhh. 

The sense of relief is palpable and you’re pretty sure you’re never going to leave the house/wear a bra ever again.

But, of course, you have to.

The good news is, you don’t need to fight a daily battle with your bra. There is a perfect bra out there for everyone, and bra-fitting expert Maxine Windram and the team at Brava Lingerie are determined to help you find it.

To help you get started, Mamamia spoke to Maxine about what women with a D+ cup need to know when they're shopping for a new bra.

Here are seven things Maxine wants you to know:

1. Majority of women are wearing the wrong-sized bra.

Yep.

We're all guilty of it.

Maxine says that more than 80 per cent of women - who haven't had a professional bra-fitting - are wearing the wrong-sized bra.

Other women will settle on their bra size early in life and stick with it, despite the changes in their body. While other women will wear what they think should be their bra size, when in fact they're a completely different size.

According to Maxine, the biggest mistake women are making is wearing a back size that's too big or a cup size that's too small.

"We conducted a study of 50 women visiting Brava for the first time," Maxine tells us. "Out of 50, just one was in the correct size. Most women were wearing a back band that was one to two sizes too big and cups that were two to three sizes too small."

Brava specialises in sizes 6-22 and D-K cups, which can often be hard to find in traditional department stores and a lot of boutiques.

2. Not all cup sizes are created equal.

As Maxine explains there's a misconception that all D cups are the same size.

"You often hear women say, 'I’m a D cup'," she explains. "But the difference, for example, between a 10D and 18D is actually four cup sizes."

When the back size increases, so does the volume of the cup. So a woman who is a 16E would have much larger breasts than a woman who wears an 8E.

To put things into perspective, the volume of these cup sizes - 20B, 18C, 16D, 14DD, 12E, 10F, 8FF, 6G - are exactly the same.

3. You shouldn't pay too much attention to the size on the tag.

Maxine says a lot of women get hung up on the size on the tag and that robs them of the opportunity to wear a comfy, supportive bra.

"Don’t pay too much attention to the size on the tag, there's no universal size," she explains. "You could have three perfect fitting bras and they will all say a different size on the tag, depending on the country or the brand." 

You're much better off wearing a comfy size 12G than a size 10DD that digs into your underarm or makes you chafe.

4. Finding the right bra can completely change your life.

Not only will finding the right sized bra stop you from having anymore #BadBraDays, but it can actually have a massive impact on your mental and physical health.

A poorly fitting bra can cause nerve damage, chaffing, neck and back pain, and even mastitis in pregnant and breastfeeding women.

Finding the right size bra can have an immediate impact on a woman's appearance and self confidence.

Maxine has seen many women completely transform in her fitting rooms.

"We see happy tears in the changing room when [women] discover not only comfort and support, but beautiful fabrics and styles that inspire confidence and self worth," she says.

5. You'll have five to seven different bra sizes throughout your life.

It's very unlikely that you'll wear the same size bra throughout your life.

In fact, Maxine says most women will wear anywhere between five to seven different bra sizes throughout their lives.

Hormonal changes like pregnancy, breastfeeding and menopause will dramatically change the size and shape of your breasts.

Some women will also experience fluctuations if they lose or gain weight.

6. You should get a regular bra-fitting.

Because your boobs change so much over your life - and bra sizes change from brand to brand - Maxine says you should make a bra-fitting a regular part of your life.

"I see a bra fit check as important as going to the dentist, having a pap smear or a mammogram," she says. "We recommend every 12 months and even sooner if a woman has gone through change such as weight loss, weight gain or hormonal changes due to pregnancy or menopause."

7.  Most importantly, a good fitting bra should feel super comfy (Hallelujah).

When you find the right bra for you it should feel like it's just meant to be.

"The wire shouldn't sit on or cut into any part of your breast, the band should sit horizontal around your rib cage. If you lift your arms in the air, your bra band should not lift off your rib cage," Maxine explains.

Maxine says, most importantly, you need to trust your own gut feeling when it comes to bras.

"If it doesn’t feel right, it probably isn’t. If you're adjusting your bra throughout the day, it's not right, if you can see any bulges in the cup it's not right."

So now that you have all the (boob) facts, visit Brava Lingerie for a professional bra-fitting and say goodbye to bad bra days forever.

Brava Lingerie has stores in Sydney and Melbourne. You can also use their award-winning virtual bra fitter if you can't make it in store.

Check out their latest collaboration with lingerie and swimwear brand Freya here.