Colostrum is the first milk produced by the mammary glands, a thick, often yellowish fluid that precedes the mother’s mature milk supply. This “first milk” is densely packed with nutrients, unique growth factors, and high concentrations of immunoglobulins (antibodies) that provide passive immunity to the newborn. It serves as the infant’s first natural immunization, protecting the developing gut and helping to establish a healthy immune system. Understanding the small, concentrated amount of colostrum a baby needs aligns perfectly with the newborn’s tiny stomach capacity in the first few days of life.
Understanding Initial Infant Stomach Size
The newborn’s stomach capacity is extremely small at birth, a physical constraint that explains why only tiny amounts of colostrum are necessary. On the first day of life, a baby’s stomach is only about the size of a small cherry or a marble. This limited capacity means the stomach can comfortably hold only about 5 to 7 milliliters (mL) at a time. This small volume is normal and prevents the infant from being overwhelmed while their digestive system matures.
The small, frequent feedings of concentrated colostrum prepare the baby for life outside the womb. The digestive tract needs time to transition to intermittent feeding after receiving constant nutrition through the placenta. This restricted size ensures the baby receives highly concentrated nutrients and immunological protection without overstretching the stomach.
Expected Colostrum Intake Volumes
The amount of colostrum a baby takes in increases rapidly over the first few days, moving from drops to milliliters per feeding.
Day 1 Intake
On Day 1, a baby typically consumes only about 2 to 10 mL of colostrum per feeding, which is roughly equivalent to a half to a full teaspoon. These tiny, frequent feedings, often 8 to 12 times within a 24-hour period, provide all the necessary calories and hydration because colostrum is so nutrient-dense.
Day 2 and 3 Progression
By Day 2, the stomach begins a slight expansion, and the intake volume per feeding increases to a range of 5 to 15 mL. This increase accommodates the baby’s growing needs and corresponds with the initial rise in the mother’s milk production. The baby’s stomach size is closer to that of a walnut by Day 3.
Transition to Mature Milk
Between Day 3 and Day 5, the colostrum begins to transition into mature milk, and the volume a baby can consume increases significantly. Feeding volumes reach about 15 to 30 mL per feeding. The baby should be consuming about 30 to 60 mL per feeding by Day 4. This progression ensures that as the baby’s stomach expands, the milk supply simultaneously increases to meet the growing demand.
Assessing If Baby Is Getting Enough
Since it is impractical for parents to measure the exact milliliter intake, monitoring the baby’s output and behavior provides the most reliable way to assess adequate colostrum consumption. The number of wet and soiled diapers serves as a direct indicator of sufficient nutrition and hydration.
Diaper Output Progression
The output should increase daily as the intake volume rises:
- On Day 1, expect at least one wet diaper and one dark, tarry meconium stool.
- On Day 2, expect two wet diapers and two stools.
- By Day 3, expect three wet diapers and at least three stools, which should begin transitioning from black to a greenish color.
- After Day 4, the baby should have four or more wet diapers.
- By Day 5, the stools should be a loose, seedy, mustard-yellow color.
Behavioral and Weight Indicators
Behavioral signs are also important indicators of effective feeding, such as audible swallowing and a look of contentment afterward. The baby should appear calm and satisfied for one to three hours between nursing sessions. Healthcare providers monitor the baby’s weight. Initial weight loss (5% to 7% of birth weight) is normal in the first few days, but the baby should begin gaining weight again by Day 4 and regain their birth weight by 10 to 14 days of age.