Maternity & Nursing Bras Common Questions

If you have questions about maternity and nursing bras, we may just have the answer here for you. We cover underwires, timelines, different types, washing your bras, and charts for getting the correct fit and size.

Breastfeeding and buying maternity and nursing bras, getting the right fit and size

Can I wear an underwire when breastfeeding?

It is recommended that towards the end of your pregnancy, during your third trimester, you stop wearing bras with underwire, as these can put pressure on your breasts where the milk ducts are starting to produce milk. Continue wearing non-underwire bras after birth for at least the first few weeks.

If you find that non-underwire bras are a comfortable choice for you, then keep wearing them so long as they still fit well and are giving you the support you need. So long as your bra is well-fitted, even when worn with breast pads added if necessary, this will be fine.

If you do return to an underwire bra after the first few weeks post-birth, it is recommended that you avoid sleeping in them as, again, it can put undue pressure on your breasts. You may also like to use a flexi-wire bra, as a nice in-between option. Two flexi-wire bras we have are the Ambition Plunge and Forever Yours (Nude and Black). 

Browse our maternity and nursing bras collection.

When will I need a maternity bra? 

You may find that you need new bras as early as the first trimester, as not only your breasts increase in size, but your rib cage too, and this will mean you need bras with both a larger cup size and band size. A typical increase may be up 2 sizes in each. (Do note that your band size is likely to go down again post-pregnancy and return to a size similar to your pre-pregnancy size as your rib cage contracts again).

What is the difference between a maternity bra and a nursing bra?

Maternity bras

A key difference between a maternity bra and a regular bra is that it has more hooks at the back for a wider range of size adjustment, giving you more wear throughout your pregnancy and then beyond. It also has either no underwire or flexiwire to make sure it is gentle on your body and ultra-comfortable.

Nursing bras

A nursing bra will have some kind of clip at the top of the cup to undo for nursing, making the cup fall for easy access to the breast, as it is then only attached to the bra at the base. Many of the clips on our nursing bras are magnetic, such as our Ambition Triangle.

Ambition Bra Triangle nursing bra by Hotmilk with nursing clips

Nursing bras often have a 'sling' underneath the cup; a discrete style sling is an 'A'-frame, whilst a Side Sling offers less coverage.

How do I wash my nursing bra?

Washing your nursing bra frequently is more important that one may first realise! Unlike before, you now have milk leaks on the regular, and this will lead to an odour if you don't wash it thoroughly before the milk goes off.

Not only that, but the smell is a result of bacterial build-up, which is not good for several reasons. It's not a good environment for sore, cracked nipples which the bacteria could enter the body through (causing mastitis), it's also not good for baby to feed from breasts that may harbour this bacteria, and it's also not good for your bra, as the material will discolour and degrade from the mold. 

When to wash your nursing bra

The best time to wash your bras are at night before you go to bed, and we suggest establishing a routine of doing this each night by hand with the one you've worn that day. So long as you have at least 3 bras, you will then always have one on dry and ready to go for the next day. 

How to wash your nursing bra

Washing your nursing bras by hand in cool, soapy water with a gentle detergent will help protect them so they last well. Then hang in your shower to drip-dry overnight and move to a shaded spot with good airflow the next morning to dry over the day.

If you do use a washing machine, again use cold water and a gentle detergent, and also protect the bras with a wash bag for delicates and set the cycle for delicate items too. Never use a dryer for your nursing bras.

Keeping clean through the day

Using nursing/breast pads to catch leaks before they go on your bra is a great way to stay fresh throughout the day. Change these as required. You can either get disposable packs or washable sets. Shop options here.

HOTmilk Bra Fitting Guide 

A well-fitted bra makes a big difference to the way you feel and look – both in, and under, your clothes.

HOTmilk maternity lingerie is designed to make you feel amazing, while also meet your needs for a practical nursing bra. See our fitting checklist below for how to get the best fit in your new HOTmilk maternity bra.

Hotmilk Bra Fitting Guide

For sizing and measurement information, check out the HOTmilk Bra Size Guides below to help you work out the best size for you.

HOTmilk Size Guides

Use this Sizing Guide to get the perfect fit when buying online from Belly Beyond! 

Please measure with a bra on. When measuring, you need to measure quite tight for your underbust measurement, and then over the bust, you measure loosely.  Otherwise your result will be incorrect.  

Bra Size Chart

Bra Size Chart

My Necessity Bra Size Guides

Use the following size guides to fit our My Necessity Bra, which is available in both regular cup and full cup sizes.

My Necessity Bra: Regular Cup

My Necessity Bra - Regular Cup

My Necessity Bra: Full Cup

My Necessity Bra - Full Cup

Sister Sizing

Sister sizing allows you to find your perfect fit. Sometimes after measuring yourself, it is possible that your size may still need to be adjusted.

The following chart shows sister sizing for each bra size. All of the sister cups in the same row are the same size.

Sister sizing is like a seesaw. If you move up in the band, move down in the cup and vice versa. For example if you find that a size 12E fits well in the cup, but is too big around the band, go down to the next sister size in the row and try a 10F.

Hotmilk Sister Sizing Chart


We hope the guides above have been helpful to you and that you have a cherished time nursing your little one. If we can offer you any more assistance, please reach out on the live chat to speak to one of our friendly team.