Returning to infancy, although researchers have generally focused on this element of wakings, there are other ways in which breastfeeding impacts sleep, ways that actually facilitate sleep. One way is simply in terms of how much sleep infants get early on. One study found that breastfed babies at 3 months of age slept a total of 40-45 minutes longer (measured via actigraphy) than formula-fed babies and parents of breastfed babies reported fewer sleep troubles[18]. This coincides with other research finding breastfeeding mothers, especially those who bedshare, report better sleep than their counterparts[19][20].
Another effect that is rarely mentioned to mothers is the transmission of certain hormones, notably melatonin and tryptophan, through breastmilk, which not only helps babies fall asleep, but actually provides critical information about the circadian rhythm.
As babies are born with no real circadian rhythm, it is something that first emerges in the first few months of life, but then continues to develop over years[21]. However, research has found that breast milk is one of the ways in which babies develop this rhythm, as the mother’s body passes on hormones at the levels she has to help the baby learn the difference between night and day[22]. Of course, this is coupled with exposure to light which helps define this difference as well (and why formula fed babies do develop this rhythm), but the effects of these hormone levels in milk have a distinct benefit for mothers that is rarely discussed.
Notably, as baby develops his or her rhythm in conjunction with Mum (if no form of disconnect occurs), babies are more likely to share a circadian rhythm with their mother[23]. This means babies are more likely to not wake early if Mum is not a morning person, stay up too late if Mum is exhausted, and so on. Now, of course, the relationship isn’t perfect and we all know those families where Mum may be breastfeeding on demand and not sleep training and still has a child with an opposite schedule to her own, but the likelihood is much less. Given many mothers find the hardest part of sleep with little ones is to do with schedules that are opposed to their own, it would seem we should be prioritising breastfeeding as a way to help cope with this.
Summary
We need, as a society, to stop trying to sacrifice breastfeeding for sleep. This isn’t just to the sleep trainers and people peddling magic sleep solutions (yeah right), but to the researchers who continue to make limiting or structuring breastfeeding a piece of their sleep interventions. Not only is this really not warranted in most situations, but may also lead to the perceived necessity of sleep training as the biological mechanisms in place to help our infants develop their sleep become compromised.
So for all you parents out there, nurse. Nurse to sleep. Nurse on demand. Nurse often. Nurse as long as you wish. Do not let anyone tell you otherwise.
References:
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Tracy Cassels, PhD is the Director of Evolutionary Parenting, a science-based, attachment-oriented resource for families on a variety of parenting issues. In addition to her online resources, she offers one-on-one support to families around the world and is regularly asked to speak on a variety of issues from sleep to tantrums at conferences and in the media. She lives in Prince Edward County, Ontario, Canada with her husband and two children.
A great article and such important information to share.