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How the Timing of Expressed Milk Feeds Can Impact Sleep

As a parent, ensuring your baby gets enough sleep is probably one of your top priorities. But if you're a pumping Mum, did you know that the timing of expressed milk feeds can also have an impact on your baby's sleep?

A recent study has confirmed what lactation experts have long suspected, that the timing of expressing milk and baby drinking it affects infant sleep.

Breast milk, it turns out, is not just a meal, it’s also a clock, providing time-of-day information to infants. The composition of breast milk changes throughout the day, with the morning milk having a different cocktail of ingredients than the evening milk. Researchers believe that this "chrononutrition" may help program the baby's emerging circadian biology, their internal timekeeper that allows them to distinguish day from night.

However, what happens when babies drink milk that is not directly from the breast, but is pumped at different times of day and stored in advance of feeding? This is a question that has rarely been considered, but the implications are far-reaching.

Infants' sleep, eating and energy levels all show circadian rhythms, which means they follow a daily cycle. But, babies are not born with these rhythms fully set, and their sense of day and night develops over the first few weeks and months of life, with the help of cues like sunlight and darkness. Some babies show predictable circadian fluctuations in hormones linked to alertness, sleep, and appetite, while others struggle to get into a schedule.

Breast milk changes dramatically over the course of the day. For example, cortisol levels, a hormone that promotes alertness, are three times higher in morning milk than in the evening milk. Melatonin, which promotes sleep and digestion, is barely detected in daytime milk but rises in the evening and peaks around midnight. Night milk also contains higher levels of certain DNA building blocks that promote healthy sleep, while day milk has more activity-promoting amino acids.

Daytime milk may also have a special immune punch, with researchers finding higher levels of key antibodies and white blood cells in day milk compared to night milk.

With the advent of breast pumps and refrigeration, breast milk can now be consumed at different times than when it was produced. What happens when babies drink night milk in the morning, or morning milk in the late afternoon? This question has been understudied, but it's plausible that offering an infant a bottle of morning milk in the evening, with its high cortisol and low melatonin levels, might be the nutritional equivalent of flipping the lights on right before bedtime.

As a breastfeeding mother, it's worth considering the timing of expressed milk feeds if your baby is struggling with sleep. By ensuring you pump and feed at similar times in the day, you may be able to help program your baby's circadian biology and promote healthy sleep patterns.

So the timing of expressed milk feeds is an important factor to consider when it comes to your baby's sleep. By keeping in mind the changes in breast milk composition throughout the day, you can help ensure your baby is getting the best possible sleep. If your baby is having sleep issues, try to ensure that the expressed milk feeds are being given at similar times each day.

Here at The Bedtime Champ I take a holistic view of sleep and look into a broad range of factors when considering issues with sleep. If you're having issues with your child's sleep, please get in touch to see how we might be able to work together.

Source: To read more about the study cited in the post above, please visit here and here.


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