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Maternity Lingerie

How to find the perfect fitting maternity or nursing bra

By Cake Maternity

Apr 22, 2021


Any boob-haver knows that shopping for a new bra is one of the most daunting tasks out there. You may be one of the lucky ones who know their perfect bra size (and there’s only around 20% of you out there!), but then you try out a new brand and realise you need to be fitted all over again.

If you throw pregnancy or breastfeeding into the mix, that’s a whole different kettle of fish. Over the course of a woman’s motherhood journey, her breasts undergo a multitude of changes, from rapid growth during pregnancy to daily (even hourly!) fluctuations during breastfeeding.

But never fear, mama! We’ve broken down the steps you can take to ensure your best bra fit EVER, even while your boobs are fluctuating like crazy. Plus keep on reading to download our free bra fitting guide!

When to measure for a maternity and nursing bra

Before we whip out the measuring tape, let’s break down exactly when you should consider measuring yourself.

During the first few months of pregnancy, we recommend mamas stick to seamless styles which cover several sizes in one. This way your boobs are free to do all of that fun early-pregnancy expansion, without any restriction (because we KNOW they’re tender, mama). Generally your pre-pregnancy size will serve you well for these first few months, as long as you’re wearing styles with lots of stretch.

By the time your second and third trimesters roll around, you’re free to introduce a flexi-wire bra to the mix.

Note: This doesn’t mean you can jump straight back into your pre-pregnancy Victoria’s Secret underwire bra! Flexi-wire is just what it sounds like, FLEXIBLE! Although your boobs have calmed down a little bit, there’s still changes happening behind the scenes.


Come your 8th month of pregnancy, you may want to consider measuring yourself for some nursing bras to use once bub arrives. This is because your cup capacity is a similar size to what it will be around 6 weeks postpartum when your milk supply has regulated! Just keep in mind your band size is likely to change as your ribcage contracts postpartum.

How to measure for a maternity and nursing bra

Okay, now that’s out of the way, let’s whip out a measuring tape! For an in-depth explanation of how to measure your bra size, you can always visit our Fitting Room. But if you’re busy preparing for bub’s arrival or caring for a newborn, ain’t nobody got time for that. Let’s break it down here.

Step 1:
Pop on your best fitting, soft cup bra.
Now wrap your measuring tape around your rib cage, just underneath your bust. Take your measurement (in inches) and round it to the nearest whole number. For example, if you measured 27.5”, you’d round this up to 28”.

Now take this number and refer to our band size chart below. A 28” measurement is a 32 band size.

bra fitting guide underbust measurement chart

Step 2:
Now take your measuring tape and wrap it around the fullest point of your bust. For most women this is roughly nipple height. Round this to the next whole number. For example, if your bust measures 34.5”, round to 35”.

Step 3:

Here comes the fun part — calculating your cup size! Deduct your band size from your cup measurement. The difference in inches can then be converted to your cup size! For example, 35-32=3. This 3” difference means you’re a C cup!

Therefore you’re a 32C (US)!

bra fitting guide cup size chart

Now if that was still a bit too confusing (we get it, even we get confused sometimes and we’re experts!), try our “Find my fit” quiz via our menu bar.

How to know if you have the right bra size

So you’ve purchased a bra in what you think is the right size, but it’s still not feeling quite right? Let’s troubleshoot!

Symptom 1: My band is constantly riding up my back!
If this is you, you can pretty much bet your band size is too big. Try going down a band size (or two), but always ensure you go up the same number of cup sizes to keep the cup capacity the same. For example, if you find a 34B rides up your back but the cups fit perfectly, give a 32C a try as this will be narrower around the band but will have the same capacity in the cups.

Symptom 2: My boobs keep spilling out the bottom of my bra!
Again, this is an indication that your band size is too large. Try going down a band size and up a cup size.

Symptom 3: My boobs are spilling out of the cups and/or the underwires are digging in!
Now we don’t want to state the obvious here, but these are sure fire signs that your cup size is too small. If your band is fitting comfortably, go up as many cup sizes as you need until your breasts are completely encased in the cups and you have a smooth silhouette.

Symptom 4: My cups are all wrinkly and gape at the top!
Unless you’ve just breastfed, this is an indication that your cup size is too big. Try going down a cup size or two until your cups fit comfortably over your breasts. If you’re nursing, always measure yourself or try on bras before you feed. This way you know your bra will fit, even if you’re a little bit engorged.
If you’re not experiencing any of these issues but you’re still not in love with the fit, you may be wearing the wrong style of bra for your shape! Our friendly customer service team is always on hand to answer any questions you may have or recommend the right styles for you.

bra fitting guide book

Bra fitting guide

Feeling a little overwhelmed? We get it. It’s a lot of information to take in! That’s why we summarised it into a handy little eBook, so you can refer back to it whenever your size changes.

For everything from the different types of maternity bras to finding the right fit for each trimester, download our Maternity Bra Fitting Guide.

Motherhood can be daunting, and the last thing you need to do during this time is spend hours hunting for the perfect bra for you. Comfort and support are our two driving forces here at Cake, and we’re always here if you need some guidance or a nudge in the right direction.

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