Nature

Colostrum in Pregnancy and After Birth

Colostrum is the “first milk” produced by the mammary glands after birth and lasts only a short time before its composition changes.1,2 For many mammals, colostrum and mature milk is essential for the survival of the newborn offspring.3 Colostrum provides nutrients for growth, energy, and development as the newborns transition from placental supply before birth to oral ingestion of complex macromolecules after birth.3 Colostrum also provides immune protection that supports the innate immunity of neonates before their system can mature and adapt to the environment.3

In humans, colostrum is not necessary for survival for infants born full-term (37 weeks’ gestation and longer), but it does provide many health benefits.3 Colostrum becomes even more vitally important for pre-term infants, who are most likely to suffer from complications in utero and in the immediate postnatal period, resulting in growth failure and high susceptibility to infections, gut disorders, lung complications, and brain damage.3 Because immune protection starts before birth with the passive transfer of immunoglobulins occurring in the last trimester of pregnancy, pre-term infants may be missing critical immune pieces and therefore require more intense intervention — or risk poor health outcomes.3 The immunoglobulins in colostrum provide a first line of defense to mark pathogens for destruction in the gut and modulate immune function in the intestinal mucosa to limit inflammation, in addition to many other benefits.3

Nutritional Composition of Colostrum

Colostrum is a concentrated source of vital nutrients and compounds that help jumpstart a newborn’s system in the first days of life and can serve as the sole source of nutrients they need. The composition changes substantially as the milk matures due to a partially open blood-milk barrier in the mammary gland around the time of birth.2,3 The primary difference between colostrum and mature milk is the concentrated presence of macronutrients and micronutrients, anti-microbial factors, immune-stimulating components, and growth factors.­1,2