What is Your Breast Milk Made of Anyway?

Have you ever stopped to wonder what your breast milk is made of? Actually, breast milk changes depending on the amount of time that has passed since delivery, the time of day, the environment, and even the mom herself. Over time, your breast milk and baby will learn to sync-up to adjust to your baby’s growing nutritional needs. Here’s what you can expect during each phase of your breastmilk development.

Colostrum (produced 0-5 days postpartum)

Colostrum is the first fluid mom produces after delivery. It contains important antibodies that help build your baby’s immune system as well as growth factors that help baby develop properly. Additionally, colostrum is an excellent diuretic that works to expel anything in your baby’s stomach left over from the prenatal phase. Unlike the movies, your milk won’t come in all at once in a waterfall fashion. In reality, your body will secrete only a small amount of fluid during the colostrum phase because your baby’s stomach can’t handle much yet anyway.

Potential Issue: Delayed milk production. While this can be an issue, as mentioned before, colostrum comes in small quantities. A lot of moms have concerns about whether they are producing enough during these first few days, but your baby only needs about 0.1–0.2 oz (or 5–7 mL) in the first day of their life. The image below depicts how much the average baby can consume in the first days following delivery:

Transitional Milk (produced starting 5-14 days postpartum)

As your baby begins to grow, your transitional milk will come in. This fat-rich fluid helps your baby receive enough calories to start gaining weight. Transitional milk has less sodium, chloride, magnesium and more potassium and calcium than colostrum. By 2–3 weeks postpartum, milk is considered “largely mature”.

Potential Issue: Possible breast engorgement as your milk comes in. This is natural but shouldn’t hurt. If you are experiencing breast engorgement or nipple pain, try chatting with Ellie to receive real-time remedies for these pesky issues.

Mature milk (by 4-6 weeks postpartum)

Mature milk is what most people think about when thinking about breast milk. It’s packed with macronutrients (proteins, fats, carbohydrates/ sugars — specifically disaccharide lactose) and micronutrients (vitamins A, B1, B2, B6, B12, D, iodine) to keep your baby hydrated and nourished so that their growth may continue. Additionally, mature milk contains “prebiotics” such as human milk oligosaccharides (HMOs) which help promote the growth of probiotics, which are the helpful types of bacteria that live inside of our digestive tract to help prevent things like diarrhea

Potential Issue: It can be hard to get baby all of the important nutrients they need in the quantities they need them, even when mom is eating a balanced diet. Adding a multivitamin may assist with this, but always check with your healthcare provider before adding any medications or supplements to your daily routine.

Even in 2017, doctors and scientists are continuing to research and learn more about the makeup of breast milk and all that it can do for your baby! If you’re interested in the scientific nitty gritty of the concepts discussed in this post, here is a link to one of our fantastic reference articles: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3586783/pdf/nihms-413874.pdf

Have more questions? Try chatting with Ellie

Ellie helps you overcome breastfeeding challenges with information verified by experienced IBCLC’s. She’ll help you identify and treat breastfeeding challenges and even connect you to Lactation Consultants for further care. Ellie is available 24/7 over Facebook Messenger. When in doubt, check with Ellie.

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Ref: Ballard, O. & Morrow, A. L. (2013). Human Milk Composition: Nutrients and Bioactive Factors. Pediatr Clin North Am. 2013 February ; 60(1): 49–74. doi:10.1016/j.pcl.2012.10.002.