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Newborn Stomach Size

Newborn Stomach Size


How much Breastmilk does my baby need?

Breastmilk production in the first 12 months follows a 3-phase pattern,
“Initiation, Secretory Activation and Maintenance.” 

Initiation Phase – The first 24 hours following birth

In the first few hours following birth, the delivery of the placenta and the release of Oxytocin stimulates the initiation phase of breastfeeding. In response to your delivery, skin to skin contact and the first breastfeed, your body begins to produce larger quantities of colostrum.

In these first 24 hours, your baby only needs a very small amount. Their stomach size resembles that of a cherry – comfortably holds 5-7ml. You will likely not produce that amount straight away however, usually much less, and this is not something to be concerned about!

As a general rule, the hungrier the baby, the more frequent the breastfeeding demand - the more stimulation for your body to increase the supply.

In addition to this, it is normal for your baby to lose weight in the first week. This should be monitored by your healthcare provider to ensure baby is healthy and well whilst losing this expected weight. 

Building Phase (secretory activation) – 24 hours to 2 weeks of age

By approximately 72 hours of age, your baby’s stomach size has grown and now can resemble the size of a walnut, (22-27mls). This means their desired intake has increased exponentially in a comparatively short period of time. This is one of the most common causes for ‘night 2 syndrome’ - when your baby seemingly wants to breastfeed almost constantly! This frequent stimulus encourages your milk to ‘come in’ – which essentially means producing larger quantities of colostrum and transitional milk. This typically occurs somewhere between 24-120 hours after birth.

This process can be delayed by many variables, so during this time, your midwife or paediatrician will ensure baby is receiving enough nutrition until this lactation phase begins.

Around the one-week mark, your baby’s stomach now resembles the size of an apricot and can comfortably hold 45-60ml of milk.  By this time, you could be producing around 500mls per 24 hours.

By 2 weeks, your baby will be back to their birth weight or more, plentiful wet nappies and will happily tolerate 80-150mls per feed (stomach size resembles an egg)

Maintenance Phase – 4 weeks to 12 months

By the time you have reached the 4–6-week mark, your milk supply will have started to settle into a stable routine. You will make approximately the same amount of milk every 24 hours going forward, provided there are no major changes in your breastfeeding/expressing routine. This amount of breastmilk was determined/decided by your baby’s demand in the first 4 weeks. This is why it is so important that you feed baby on demand, avoid unnecessary top-ups and focus on the quality of feeds rather then the timing. As baby gets older and more mature, they become more efficient on the breast and may feed less often, or the opposite may also be true, frequent small ‘snacks’ – this varies, depending on your baby’s behaviour!

It is also important to note, that while these representations are used to describe a baby’s intake, they are only an approximate guide – babies will often demand (and tolerate!) more breastmilk, usually whatever you have available in the first 2 phases of lactation. Much like us, their appetite varies feed to feed, some feeds will be better quality and productivity then others.  It is best to monitor their intake in other ways, their urine output, weight gain, behaviour and ability to settle between feeds. If you are ever unsure your baby is receiving enough milk, check in with your midwife or allied health professional to be sure!

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


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