When a mother brings her baby to the breast, many things happen concurrently with breastfeeding. Skin-to-skin contact occurs every time the baby sucks at the breast, which helps warm the baby up and stabilize the heart and respiratory rates.¹ Oxytocin is released, decreasing mom’s chance of hemorrhage immediately after birth and increasing bonding as mom and baby get to know each other.^2,3 Bringing baby to the breast also gives mom and baby a chance to recalibrate from a stimulating new life. These steps together form an engaging dance between mom and child, a dance that comforts, warms, and protects baby. Among all the steps of this dance, there is one that is only available to baby during the first few days of life, although present since mid-pregnancy. It is consumed briefly and only in small amounts, but its impact is vast. Colostrum.

Low in fat but high in protein and immunoglobulins, colostrum is extremely easy to digest and acts as a laxative. The laxative effect of colostrum is essential for an infant working on passing his first stool, meconium. The passage of meconium and subsequent early stooling will assist with the removal of excess bilirubin before being reabsorbed back into the bloodstream. Since jaundice is the product of elevated bilirubin concentrations in the blood, infants who do not pass meconium quickly are at greater risk of jaundice due to the reabsorption of bilirubin present in the infant’s stool.⁴ Colostrum gets to work immediately by assisting baby’s very first bowel movement!

Baby’s gut is permeable during the early days to weeks of life, leaving your baby at greater risk to allergens and pathogens passing through the loose junctions between gut cells.^5,6,7 Once these allergens escape the gastrointestinal tract and enter baby’s bloodstream, sensitization can occur, leading to serious food allergies or other illnesses.⁵ Present in breastmilk are various types of human growth factors, including epidermal growth factor, nerve growth factor, insulinlike growth factor, and somatomedin C, with epidermal growth factor having the highest concentrations in colostrum.⁷ These growth factors work to seal the loose junctions in the gut, so baby isn’t as vulnerable to his new microbial environment.^5,7

Sealing baby’s gut isn’t the only way colostrum helps to ensure the health of a brand-new infant whose immune system is relatively immature.⁸ While in utero baby receives immunoglobulin G or IgG via mom’s placenta. IgG is useful but works only in baby’s circulatory system.⁹ Another immunoglobulin, secretory Immunoglobulin A, or sIgA, is highly concentrated in colostrum and works where baby is most likely to experience pathogenic insult, the mucous membranes of the throat, lungs, and intestines.⁹ Colostrum has 13 grams per liter of this valuable immunoglobulin, while mature milk has 1 to 3 grams per liter. That’s a big difference!^10,11 Even with this drop in concentration, it is important to note that overall daily production levels of sIgA remain consistent for the duration of breastfeeding. However, as your colostrum transitions to mature milk, the sIgA concentrations are diluted with other essential nutrients baby needs to grow.^10,11 Considering that baby’s immature immune system is experiencing the world of pathogens for the first time, it makes sense why sIgA concentrations are so high initially—small amounts of milk for a small tummy but large amounts of immunoglobulins for a large world.

Even in amounts small enough to be measured in teaspoons, colostrum is just what baby needs to fill up his little tummy. A baby’s stomach is quite small during the first day of life, about the size of a shooter marble; this means no more than a few drops to one teaspoon (5 mls) is all baby needs to be satiated.^12,13 As a new baby contentedly suckles at the breast, he enjoys a feast that fills up his tiny tummy with the exact volume and content he needs. Although 5 milliliters may not seem like a meal to mom, it is undoubtedly a complete meal for baby on his first day of life. Due to the rigid nature of the newborn stomach, consuming more than the small amount a mother’s body makes will result in regurgitation as baby gets rid of what his inflexible stomach cannot accommodate.¹⁴ So while mom blows raspberries on that smooshy belly, she can know that, like puzzle pieces, her colostrum and baby’s stomach are a perfect match!

With this knowledge of infant anatomy, one can understand the importance of a low volume but nutrient-dense food for infants during the first few days of life; it also gives a clear reason for all those short but frequent feeds baby asks for. Frequent feeding, along with infant growth, relax the stomach, and by the end of the first-week baby will enjoy larger meals of 1.5 to 2 ounces.^12,13,14 By one month, there is quite a bit more variation. Some babies will continue to enjoy just one-and-a-half ounces per feed, while others will take four-and-a-half ounces.^12,13,15 This means if a baby prefers meals on the smaller side of normal mom is likely to receive requests from baby to feed more often. Some mothers report feeding their babies every hour. These early weeks can seem like a lifetime. The days are long, but the year is so very short, and soon enough mom will be the one bugging her toddler to come sit down and eat.

As milk transitions from colostrum to mature milk, mom will likely notice some changes in her breasts and her baby. Baby’s sucking pattern will evolve to include more gulping. Mom’s breasts may begin to leak or feel fuller.¹⁶ Some mothers report no noticeable changes in their breasts while others report discomfort and engorgement, but the most notable changes will be in baby’s bowel movements. During the first day or two baby’s stools will be a thick, greenish-black meconium. The few days that follow, the stools will become less black and green to yellow as mom’s breasts fill with mature milk. The entire process of milk transitioning from colostrum to mature milk usually takes three to four days, with the visual changes in baby’s stool taking about one week.^4,17

Like a couple learning the tango, mom and baby need each other to engage in their dance. A woman’s body is designed to feed her baby, and her baby is designed to receive food from her. This dance starts on the first day as mom’s colostrum helps baby acclimate to life outside the womb and continues throughout the breastfeeding relationship. Sometimes it will be graceful, and sometimes they will stumble. Each step pieced together, each partner giving and taking. At the end, there is a dance filled with conversations without words and beautiful nuances that contribute to baby’s physical and emotional development. From the time mom and baby take their first steps as a breastfeeding dyad to the very last nursing session, they are dancing with endless purpose.

Link to published article can be found here.

References:

1. Moore ER et al. (2012). Early skin-to-skin contact for mothers and their healthy newborn infants (Review). Retrieved from http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD003519.pub3/pdf on March 26, 2015.
2. Uvnas-Moberg K. Neuroendocrinology of the mother-child interaction. Trends In Endocrinology And Metabolism: TEM 1996 May;7(4):126-31.
3. Ross HE, Young LJ. Oxytocin and the neural mechanisms regulating social cognition and affiliative behavior. Front Neuroendocrinol 2009 October;30(4):534-47.

• Fisher, Denise. “Breastmilk: Composition and Function.” Educational handout. Health e-learning. n.d. Online.

• Mohrbacher, Nancy and Kathleen Kendall-Tackett. Breastfeeding Made Simple: Seven Natural Laws for Nursing Mothers. Oakland: New Harbinger Publications, Inc, 2010. Print.

• Vukavić T. Timing of the gut closure.  J Pediatr Gastroenterol Nutr. 1984 Nov;3(5):700-3.

• Jack Newman, MD, FRCPC 2011, How Breast Milk Protects Newborns, Viewed 1 June, 2015

<http://kellymom.com/pregnancy/bf-prep/how_breastmilk_protects_newborns/>

• Huggins, K. The Nursing Mother’s Guide to Weaning. Boston, MA: Harvard Common Press, 2007.

• 2006, What is Colostrum? How does it benefit my baby?, Viewed 7 June, 2015 <http://www.lalecheleague.org/faq/colostrum.html>

1. Picciano MF (2001) Nutrient Composition of Human Milk

1. Slusser W et al. (1997) Breastfeeding update 1: immunology, nutrition, and advocacy

1. Scammon RE et al. (1920) Observations on the capacity of the stomach in the first ten days of postnatal life

1. Kent JC et al. (2006) Volume and frequency of breastfeedings and fat content of breast milk throughout the day

1. Zangen S et al. (2001) Rapid maturation of gastric relaxation in newborn infants.

1. Saint L et al. (1984) The yield and nutrient content of colostrum and milk of women from giving birth to 1 month post-partum

1. 2011, When Will My Milk Come In, Viewed 1 June, 2015

<http://kellymom.com/bf/concerns/mother/when-will-my-milk-come-in/>

1. “Is my breastfed baby getting enough?” Educational handout. La Leche League International. September 2008. Print.