Other than a virtual guarantee that your breasts will get bigger (an average 300-500g each!) you can’t predict what will happen to your breasts during pregnancy.

We are all different but usually the biggest increase in actual breast size takes place during the first three months.  In fact some women experience changes in the first week or two!

With so many changes happening so fast, Margaret McLachlin, professional bra fitter and owner of More Than A Handful, has advice on all the essential know-how to ensure you buy the right maternity bra.

What happens to breasts during pregnancy?

Pregnancy hormones trigger increased blood supply to the breasts and glandular development which can result in a feeling of ‘fullness’ particularly on the top and sides of the breasts.  During your pregnancy, your breasts will continue to grow with possible tenderness as the glands continue to expand in preparation for breastfeeding.

What is the difference between my everyday bra and a maternity bra?

Maternity bras are designed to expand with the breasts without cutting into the skin and have an integrated support system for the expanding breast. They should be made from or lined by a soft non-irritant fabric and have wider padded straps to ease strain on the neck and back.

And nursing bras?

These have the same design features as a maternity bra but also have (usually a clip) a method of opening to allow easy and comfortable access to the breast with an internal breast support which stays in place while you feed.

When should I change my bra during pregnancy?

You should have your first bra reassessment at 6-8 weeks of pregnancy or as soon as there is a noticeable change in your bust size or shape. You can move into a maternity bra at this stage or change your bra to a style more suitable for support.

If these bras remain comfortable then you can wear them until your nursing bra fitting but if they become restrictive you should be refitted prior to 36 weeks of pregnancy.

What should I look for in a maternity bra?

Ultimately you want a comfortable bra which encases the breast both at the sides and at the decolletage. The bra should feel like it is supporting the breast and there should be no back or shoulder discomfort. The material should feel soft on your skin and non-abrasive. The back fastening should be on the tightest or second tightest fitting to allow for expansion of your diaphragm as your baby grows.

When should I get my nursing bra?

At 34-36 weeks of pregnancy – by this time the breast should have stopped growing and we can more accurately determine your final breast size. A nursing bra should be fit on the loosest hook because you will lose some diaphragm size when your baby is born so the bra will need to come in at the back then. Also leave a little room in the cup at this fitting to allow for expansion when your milk comes in.

What about underwire?

Many pregnant women prefer underwire, as it provides a better shape and comfortable support for the heavier breasts. Choose a maternity bra which has soft, flexible underwire which is widely placed and does not touch the breast tissue. Try to have at least one non-underwire bra for periods of increased engorgement (like just after baby’s birth) or ‘comfort days’ – the days when you just want to rest at home.

Whatever you decide to do, make your choice based on comfort and support – your bra or its underwire should never compress the breast tissue as this affects blood and lymphatic drainage into and out of the breast and increases the risk of problems occurring.

How many bras do I need?

You will need two bras during pregnancy and three or four bras while breastfeeding as the increased moisture associated with nursing will increase how often you need to wash your bras.

Do my bras need to be ugly?

No! There are a lot of prettier styles and colours available now in maternity bras. What is available to you will depend on the size of your bust. But remember this is the time when support is more important than fancy lace. If you must have a plunge bra when you are pregnant keep it for special occasions, and give those breasts some love and care the rest of the time.

How do I wash my bras?

Hand wash in warm water and mild detergent or soap. No bleach, no clothes dryers and no sun, please ladies!

How long should I wear my maternity or nursing bra?

For the whole period you are breastfeeding, or if you don’t breastfeed for six weeks after delivery to allow your breasts good support while they are changing structure again. And your bra is not designed to last more than 12 months or be saved from one pregnancy to the next! So get refitted every 12 months please.

And back to normality?

Your breasts will have changed structure and shape forever so you’ll need to get refitted for a new, beautiful bra!  When? Six weeks after you stop breastfeeding.

This article was written for Kidspot, New Zealand’s best pregnancy resource. Sources include professional bra fitter, Margaret McLachlin, owner of More Than A Handful.