Colostrum

Colostrum is the first milk the breasts produce. According to the NHS, it is "thick and usually a golden yellow colour" and serves as a highly concentrated food, meaning a baby requires only a small amount — approximately a teaspoonful — at each feed in the earliest days. La Leche League GB describes it as "concentrated milk produced in the first few days" that transitions gradually from golden to bluish-white as mature milk develops.

What does colostrum contain?

Colostrum contains antibodies that help protect a newborn from infection and support immune system development. The NHS notes it also helps the baby's digestive system to develop, which may protect against allergies, and encourages the baby to pass meconium — the first dark stool — which reduces the risk of jaundice. NHS Trust guidance describes colostrum as containing "vital immunological properties" and as helping to "colonise your baby's gut with healthy bacteria."

When does colostrum change to mature milk?

Colostrum is present from around 16 weeks of pregnancy and is the milk available at birth. Over the first days after birth, it gradually transitions to transitional and then mature milk as the breasts begin producing greater volumes. The NHS notes that babies may feed very frequently in the early period — "perhaps every hour to begin with" — before moving to fewer, longer feeds once mature milk comes in.

Why is colostrum described as important for newborns?

Because colostrum is produced in quantities that match a newborn's stomach capacity and is rich in protective factors, La Leche League GB states it is made "in just the right amounts for your baby's tiny tummy." NHS Trust resources note it helps protect against gut damage and infection, particularly relevant for babies born preterm or admitted to neonatal intensive care.