How to Choose a Nursing Bra: A Step-by-Step Guide

Quick answer

Choose a nursing bra by measuring your underband and bust now, then fitting the band snugly on the loosest hook so you can tighten it as your ribcage settles. Prioritise soft, flexible cups that open easily and allow for size changes, and add a wire free option for sleep. Recheck the fit after your milk supply establishes, because one bra rarely fits every stage.

A nursing bra has to do two jobs at once: support a bust that changes size and shape, and open quickly enough to feed a hungry baby without a struggle. That is why the most common mistakes happen before you buy, not after. Most people choose a size based on their pre-pregnancy bra, then wonder why the band rides up or the cups dig in.

This guide walks through the order that works: measure, choose the band, choose the cup and opening style, then test it against real feeding positions. It also covers when to size up, what to avoid for sleep, and how to tell whether a bra is genuinely comfortable or just tolerable for an hour.

Step 1: Measure at the right time

Measure your underbust and full bust before you shop, ideally in the morning before a feed when your breasts are fullest. Keep the tape level and snug, not tight. Write both numbers down. If you are still pregnant, measure now and plan to remeasure once your milk supply establishes, usually a few weeks after birth, because ribcage and cup size often shift again.

A common mistake is measuring over a padded bra or measuring when you are engorged. Both distort the number. If you are between sizes, start with the larger band and use the hook adjustment to tighten, rather than buying a band that is already tight on the loosest hook.

• Checkpoint: the tape should sit level around your back, not ride up.
• If your measurement changes by more than one size after birth, refit rather than making do.

Step 2: Choose the band before the cup

The band does most of the support work, so it deserves the first decision. A new nursing bra should fasten comfortably on the loosest hook. That gives you room to tighten it as the band relaxes with wear and washing. If you have to start on the tightest hook, the bra is already too small and will not last through the feeding months.

Check the band by lifting your arms and bending forward. If the back rides up or you can fit more than two fingers under the band, go down a band size and up a cup size. This is the single most common fit error, and it is also the easiest to correct before you buy.

• Checkpoint: band stays level when you reach overhead.
• Do not size up in the band to fix cup spillage; fix the cup instead.

Step 3: Match the cup and opening style to your routine

Cup style affects how easy feeding is in practice. Soft, flexible cups with stretch accommodate size changes through the day and are more forgiving if you are between sizes. Structured or moulded cups can look smoother under clothes but may not flex enough during engorgement. If you want a smoother line under fitted tops, look for a seamless finish rather than a rigid cup.

Opening style matters just as much. One-handed clips or pull-aside designs are easier when you are holding a baby. Test the opening motion with one hand before committing, and check that the cup folds down out of the way rather than springing back. For night feeds, a pull-on wire free style is often simpler than clips in the dark.

• Checkpoint: you can open and close the cup one-handed.
• If you plan to pump, check whether the cups work with your pump setup before buying multiples.

Step 4: Test it in real feeding positions

A bra that feels fine standing in a fitting room can fail the moment you sit down to feed. Wear it for a full day before removing tags, and try it in your usual feeding positions: sitting upright, lying down, and holding the baby across your body. Look for straps that stay put without digging, and cups that do not crease into the breast tissue.

Pay attention to the underband and side seams. Red marks that fade within an hour are usually normal; marks that persist or feel sore are a sign the band or cup is wrong. If the straps slip, adjust them, but if they still slip after adjustment, the band is likely too loose.

• Checkpoint: no persistent red marks or sore spots after a full day.
• Keep one bra in your pre-birth size only if it still fits comfortably; otherwise pass it on.

Step 5: Build a small rotation, not a big one

Most people need three to four nursing bras in active rotation: two for daytime, one for sleep, and one spare for laundry day. Buying a large set before your size settles is a common and expensive mistake, because early bras may not fit once supply regulates. Start with a small, flexible rotation and add more once you know what works.

Wash nursing bras gently and rotate them so elastic recovers between wears. If a bra starts needing the tightest hook to feel supportive, it has reached the end of its useful fit and should be replaced rather than stretched further.

• Checkpoint: three to four bras cover most feeding routines.
• Replace rather than repair once the band no longer supports on the loosest hook.

Your nursing bra fit checklist

1. Measure now, remeasure after supply settles: Take underbust and full bust measurements before shopping, then check again a few weeks after birth when size changes slow down. If the numbers moved by more than one size, refit before buying more.
2. Fasten on the loosest hook: A new bra should close comfortably on the loosest hook so you can tighten it as the band relaxes over time. Starting on the tightest hook means the bra is already too small.
3. Check the band with movement: Reach overhead and bend forward. The band should stay level and you should not fit more than two fingers underneath. Riding up means go down a band size and up a cup size.
4. Test the cup opening one-handed: Open and close the cup with one hand, then check the cup folds down and stays out of the way. If it springs back or needs two hands, it will frustrate you during feeds.
5. Wear it for a full day before removing tags: Try sitting, lying down, and feeding positions. Watch for persistent red marks, sore spots, or slipping straps. Marks that fade are fine; marks that linger mean the fit is wrong.
6. Start with three to four bras: Two daytime, one sleep, one spare covers most routines without overspending before your size settles. Replace a bra once it only supports on the tightest hook.

Products that fit this process

• Cotton Rich Pull On Sleep Bra: Wire free and seamless construction with a soft cotton rich pull-on design for sleep, lounge, and light support. A practical night-feed option when clips are fiddly in the dark, and a gentle choice if you want light support without underwires.
• Maternity High Neck Bodysuit G-String | ButterFit: Made from an ultra-soft, second-skin fabric with exceptional stretch that moves and grows with you and supports the bust and baby bump without feeling tight or restrictive. Useful as a smooth layer under clothing when you want coverage and stretch through pregnancy and early feeding days.
• Everyday Contour Minimising Bandeau - 2 Pack: Double-layer, high-compression knit fabric designed to reduce the appearance and size of the bust under clothing, with a slightly longer front for extra coverage. A good choice if you prefer a lower-profile look under outfits, but it is not a feeding bra, so pair it with a nursing option for feeds.

A good nursing bra is one you can open without thinking and wear all day without adjusting. Measure at the right time, start on the loosest hook, and test the fit in real feeding positions before you commit. If you get those three things right, the rest of the nursing bra guide becomes much simpler.