Expressing Breast Milk: Sterilising and Storage

Some mums are solely reliant on expressing breast milk whether that’s because it’s a medical need as their infants were born prematurely, unwell or unable to feed directly on the breast. A few mums also choose to exclusively express breast milk through personal choice.

However, for the majority of mums expressing is usually used to compliment the flexibility of nursing on the breast, for their partner to get involved in feeding, to enjoy an evening off or to help the transition when returning to work.

There is lots to consider when expressing and a few facts that are good to know, here we have compiled a little guide which may come in handy…

When can I express?

Unless you have been advised to express by a health professional or midwife to support feeding challenges or milk production, we would advise waiting until little one is 4-6 weeks to start expressing. This will give you both time to get lots of practice at feeding, latching, positioning and to build your milk supply.

There are so many breast pumps, how do I choose the right one?

Many mums presume that a breast pump is an essential part of your baby equipment. In reality this is not the case. We’d always advise you wait until after birth to decide if you need a breast pump and what pump would be best suited to your needs.

More information about choosing the right breast pump can be found on our website.

I have my breast pump – what next?

It is important that you read the instructions for use (IFU) and wash your milk collection set before its first use.

Cleaning milk bottles

How do I clean my Milk Collection Set?

As Medela is a global company we recommend using a standard method of cleaning which is available in most homes around the world – simply running water and a cooking hob.

  1. Disassemble all of the milk collection parts – bottle, valves, membrane, connector and funnel
  2. Wash your milk collection set under running cold water – this removes any milk residue. Follow with a hot soapy wash with domestic detergent, rinse under running water and dry with a paper towel.
  3. You can store your dry Milk Collection Set in a tupperware container or a zip lock bag. Ensure it is thoroughly dry before storing.

How often do I need to Sterilise my Breastmilk Collection Kit?

We recommend you sterilise your Milk Collection Set at least once a day. You may choose to do this more frequently but the minimum recommendation is you sterilise once a day to ensure all components are kept it in tip top condition.

Sterilising breast milk bottle

How do I sterilise my Milk Collection Kit after use?

On the Hob:

  1. Immerse your milk collection set components into cold water in a pan on the hob, making sure that you have no air gap in the bottle.
  2. Bring to boil and ensure that you have enough water in the saucepan to cover all parts. Boil for 5 minutes.
  3. Allow water to cool and dry the parts with a paper towel and store or use immediately.

In the Microwave:

You can use a microwave steam bag, microwave steam steriliser or steam steriliser – follow the manufacturer’s instructions for use.  Also a dishwasher can be used – be cautious about using alongside your bolognaise sauce as it can stain the plastic.

Cold Water Chemical Sterilisation

Cold water chemical sterilisation is not recommended for breastmilk collection sets, breast shells or nipple shields as the solution often leaves a residual taste and smell. This may influence your triggers for let-down, weaning off shields, may bleach your clothing and if the solution isn’t rinsed off the product it may leave a small residual and affect the composition of the milk.

Hospital guidelines may differ and we would recommend you follow local guidelines if your baby is hospitalised.

Collecting Milk

Many infant feeding bottles are now BPA free plastic and are regulated very strictly. With Medela breast milk bottles we use a standard neck and start with small bottles. On average a mum would express around 54-234mls (1 or 2 breasts) so it’s important to use the right bottle size to make it easier for you.