The term ‘mixed feeding’ refers to the practice of giving your baby formula as well as breastmilk and/or breastfeeding. Some mothers choose to mixed feed for various reasons, or are unable to exclusively breastfeed due to extenuating circumstances.

Mixed feeding can be a delicate balance however, as formula introduction and ongoing use can decrease your breastmilk supply.

How can formula impact my breastfeeding?

In the first 4-6 weeks, your body is very attuned to your baby’s needs.  Every time your baby demands at the breast, your body adjusts your supply according to the feeding frequency and amount of milk removed. This is to establish an exact supply demand pattern, and following this 6-week period your breastmilk production every 24 hours remains reasonably stable.

If you were to introduce regular top-up bottles in this time, you are effectively telling your body whatever milk is removed at just the breastfeed is ‘enough’ and there’s no need to produce more. Your body doesn’t know your baby had/needed the formula. This can begin a vicious cycle as it decreases your supply over time, which in turn, requires more and more supplemental feeds.

Other complications can follow this such as:

• Blocked ducts
• Mastitis
• Teat confusion

So, what if you’re worried your baby isn’t getting enough?

You aren’t alone! In fact, one of the most common reasons for early weaning is due to perceived low supply. With newborns typically feeding frequently (every hour some cases!) it’s no surprise mothers often doubt their baby is getting enough milk at the breast.

Other reasons why mothers may suspect insufficient milk supply include:

• Inability to express colostrum before birth
• Baby not settling or frequently demanding
• Small breasts
• Long/short breastfeeds
• Breasts feel softer/lighter than they did in the early weeks
• Unable to express as much breastmilk as before
• Frequent feeds/night waking

Despite many women’s fears - scientific research shows that, actually, only a small percentage of women are unable to produce enough breastmilk. Instead, its important first to consider the ‘whole picture’ and ensure that you do not introduce supplemental feeds unnecessarily.

Some commonly recognised signs of adequate milk intake in babies:

• 5+ clear heavy wet nappies in 24 hours (or 7+ smaller wet nappies!)
• Baby is alert and active
• Content when awake (within reason)
• Reaches expected milestones within reasonable timeframe
• Absence of diagnosed underlying conditions for mother or baby that may inhibit milk transfer (insufficient glandular tissue, oral restrictions such as tongue ties, medications etc)

Premature delivery

For some mothers, mixed feeding is unavoidable (at least in the short term!). This can be due to extenuating circumstances such as premature delivery.

Depending on the gestational age that your baby was born, he/she may not have the physical maturity/stamina to suck effectively and for long periods at the breast. This is often due to lack of muscle or fat development in their face, cheeks and ligaments. Premature babies also lack the strength to support their head with weak neck muscles – proving difficult when breastfeeding.

For example, babies born at 34-35 weeks gestational age often have an uncoordinated suck and inconsistent tongue/jaw movement. They can tire easily, and their energy requirements are higher than that of a term baby. This is commonly why premature babies require milk via a nasogastric tube (NGT) which is usually inserted after delivery and remains in place until baby is able to manage ‘all suck’ feeds. This can be a slow and steady transition, with baby attempted at the breast (when possible) then offered the remaining milk via NGT.

During this time, mixed feeding can be unavoidable until your milk supply increases. However, if you are able to provide even small amounts of colostrum/breastmilk, this should be offered first as the priority prior to any donor breastmilk or infant formula.

What if I want to mixed feed anyway?

Just like any aspect of infant feeding, your choices should be discussed and supported by your healthcare provider to empower you to make informed decisions. Breastfeeding exclusively is not for everyone, and many mothers do go on to have a successful mixed feeding journey.

Whatever you decide, it is important for you to understand the basic physiology of lactation and how this is impacted by formula introduction and ongoing usage.

If you choose to offer top-up formula feeds but want to still give breastfeeding a chance, then:

• Offer both breasts first for a feed prior to offering a top-up
• Only offer small top-ups at a time, you can feed more frequently instead
• Use the paced bottle-feeding technique to help avoid over-feeding your baby

Written by Keryn Thompson RM & IBCLC (L-301766)

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