Breastfeeding can give your baby higher levels of cortisol, but this is not necessarily a bad thing in any way.
Most of us had the privilege of being breastfed by our mothers, but for some of us that was not an option for various reasons. The connection between mother and child is a strong one. From conception to birth our mothers house us, give us nutrients, love us, and generally give us everything that we need to grow from an embryo to whom we are today. Breastfeeding is a continuation of that love in the form of nutrients, and immune cells. However, recent studies have also shown that there is a connection between the mother’s stress level and how the baby responds in the present moment, and also how their own stress level is shaped for their future.
Jena Pincott wrote an amazing article called When Stress Comes with Your Mother’s Milk; stress hormones in breast milk may help prepare us for a turbulent world. In the article she talks about how her own daughter responded to her stressful events with some of the same reactions that she was feeling. The only connection was the breast milk that she was pumping. Cortisol, the stress hormone we release in response to our daily lives, is passing into our babies, and studies have shown that breastfed babies “have an average [of] 40 percent more cortisol in their system than their formula-fed peers, suggesting that the increase comes from milk.”
The increased cortisol levels do not make me want to tell patients to stop breastfeeding, no, since there are so many wonderful, vital components to breast milk that must be considered like the vitamins, minerals, nutrients, and immune cells to name some. What this does make me stop and think about is the long term effect of the cortisol on the baby, and if any of the effects, if they do exist, are negative, or not. If they are negative then how do we get the mother to destress? Is this a societal problem in general that must be tackled?
I am not sure we have the long term answer on how cortisol in the breast milk affects the outcome of who we are as people. This is impart because cortisol is just one component of how we are shaped as humans. Scientist have been doing animal studies on this subject, and have concluded that rats offspring, given higher amounts of cortisol, “learned faster, had better memories and were less anxious and more exploratory during stress tests, suggesting a better ability to cope.” It should be noted that when the study was done on primates the effects seems to be the opposite. The more cortisol found in the baby monkey then the more timid and shy the monkey was when exposed to a stressful event. Human observations have shown a significant association with higher cortisol levels and nervous, jittery babies. More so in girls.
As a soon to be mother, this information scares me somewhat. My child’s future demeanor might be affected by my stress level, and the resulting cortisol level in my breast milk. No matter what my stress level is, be it none or high, there is still going to be some cortisol in the breast milk. However, cortisol is not the only thing that is going to help my child be shaped into the person they will become. Their genetics, nurture, life, and many other factors will go into shaping my child as much as any cortisol level could, and just like how those factors shaped me in my own early development. So Mom thank you for your breast milk, and all of your love and support. I am who I am because of everything in life, but not least of which was the breast milk I was fed as a baby.