How long does it take for colostrum to kick in?

October 30, 2025 •

4 min read

According to the Cleveland Clinic, a mother's body begins producing colostrum, or "liquid gold," as early as 12 to 18 weeks into pregnancy. After birth, how long does it take for colostrum to kick in and what are the signs that your baby is receiving this vital first food?

Quick Summary

This guide explains the timeline for colostrum production and its transition to mature milk after birth. It details the benefits for the newborn's immunity and gut health and provides signs indicating the baby is getting enough of this nutrient-rich milk, helping new parents navigate this critical phase.

Key Points

Immediate Availability: Your body begins producing colostrum during pregnancy, and it is available for your baby immediately after birth, often within the first hour.
Small, Concentrated Feeds: Newborns have small stomachs and only require tiny amounts of this nutrient-dense "liquid gold" in the first 72 hours.
Signs It's Working: Look for frequent swallowing, satisfaction after feeds, and changes in diaper output (from meconium to yellow stool) as signs your baby is getting enough.
Transition to Mature Milk: The change from colostrum to transitional milk (days 3-5) and then mature milk (around 10-14 days) is a gradual process where volume and composition change.
Factors Can Cause Delays: Stress, C-sections, or certain health conditions can sometimes delay the increase in milk supply, but frequent nursing or hand expression can help.
Early and Often is Best: Frequent breastfeeding or milk expression in the early days is the most effective way to establish a robust milk supply and ensure your baby receives the full benefits.

Colostrum: Nature's First Immunization

Colostrum is the first milk produced by the breasts, a thick, nutrient-dense fluid that is crucial for a newborn's health. Its high concentration of antibodies, proteins, and growth factors acts as a natural immunization, protecting the baby's vulnerable digestive and immune systems in the first days of life. Its rich, golden color has earned it the nickname "liquid gold". While its presence might not be noticed during pregnancy, it becomes readily available for the baby immediately after delivery. The key to maximizing its benefits is frequent, early feeding to stimulate milk production and ensure the baby receives this concentrated nutrition.

The Immediate Postpartum Period: When Colostrum Arrives

Within the first hour after birth, and sometimes even sooner, your body is ready to provide colostrum. The hormonal shift following the delivery of the placenta signals the breasts to initiate milk production. For most healthy newborns, a small amount of colostrum is all they need in the first 24 to 72 hours. Their stomach is very small, about the size of a marble, so the concentrated nature of colostrum provides ample nutrition in tiny, easily digestible quantities. This initial phase is about frequent, small feeds to coat the baby's gut with protective antibodies, rather than large volumes. The more the baby nurses, the more the breasts are stimulated, which in turn helps establish a robust milk supply for the later stages of lactation.

Timeline: Colostrum to Mature Milk

The transition from colostrum to mature milk happens in a series of stages over the first couple of weeks postpartum. This is a gradual process where the milk's composition, volume, and appearance all change to meet the baby's evolving needs.

Days 1-2: Colostrum Phase

Volume: Small, often 2–20 ml per feed.
Appearance: Thick, sticky, and yellowish due to high beta-carotene content.
Composition: High in protein, antibodies, and white blood cells, and lower in fat and sugar.

Days 3-5: Transitional Milk Phase

Volume: Increases significantly as your milk "comes in".
Appearance: Becomes thinner, lighter, and more voluminous.
Composition: A mix of colostrum and mature milk components, with increasing fat and sugar content.

Days 10-14 and Beyond: Mature Milk Phase

Volume: Full milk supply is established, producing 500-1000 ml per day.
Appearance: Thinner and more watery, with a bluish-white color.
Composition: Contains a balanced mix of fats, carbohydrates, proteins, and water to meet the growing baby's needs.

Comparison Table: Colostrum vs. Mature Milk


Feature	Colostrum	Mature Milk
Appearance	Thick, yellow, sticky	Thinner, watery, bluish-white
Composition	High protein, antibodies, low fat	Balanced fats, carbs, proteins
Volume	Small quantities (tsp amounts)	Larger, more plentiful volume
Function	Immune boost, gut protection, laxative effect	Primary source of ongoing nutrition and hydration
Digestion	Easy to digest for newborn's tiny stomach	Tailored for growing baby's expanding stomach

How to Tell if Colostrum is "Working"

Because colostrum is produced in small amounts, it's natural for parents to wonder if their baby is getting enough. Rather than the volume of milk, the key indicators are a baby's behavior and their diaper output.

Feeding Cues and Behavior: A baby receiving enough colostrum will show signs of satisfaction after feeds, settle well, and be alert when awake. Early feeding cues include rooting, sucking on hands, and restlessness.
Diaper Output: In the first 24 hours, one or two wet diapers are normal due to the concentrated nature of colostrum. As intake increases, this will progress to 6 or more wet diapers per day by day four.
Meconium Passing: The laxative effect of colostrum helps the baby pass meconium, the sticky, dark first stool. You should see stool transitions from black to green to yellow.
Weight Maintenance: While it's normal for newborns to lose some weight in the first few days, a healthy colostrum intake helps to regulate blood sugar and minimizes excessive weight loss.

Factors Affecting Colostrum Timing

While colostrum is immediately available after birth, some factors can influence the timeline for milk production and the transition to mature milk. For example, first-time mothers might find the process takes a bit longer compared to those who have breastfed before. A cesarean section, excessive blood loss during birth, or maternal health conditions like diabetes can sometimes delay milk "coming in". A traumatic or stressful birth experience can also affect milk supply. In such cases, continued skin-to-skin contact, frequent feeding, and seeking support from a lactation consultant are highly recommended. Even if mature milk is delayed, hand-expressing and providing any available colostrum is incredibly beneficial for the newborn.

Conclusion: The First Few Days Are Key

For most new mothers, colostrum is present immediately following birth, providing a perfect first meal rich in immunity-boosting properties. The small, concentrated amounts are exactly what a newborn's tiny stomach needs. Signs that colostrum is "kicking in" include regular diaper output, passing meconium, and a baby who seems satisfied after frequent, small feeds. The transition from colostrum to transitional and then mature milk occurs over the first two weeks postpartum. Remember, breastfeeding is a journey of learning for both mother and baby. If you have any concerns about your milk supply or your baby's feeding, don't hesitate to contact a lactation consultant or healthcare provider. Your baby's health in these first days is built on this precious, readily available liquid gold.

International Breastfeeding Centre: Hand Expressing Colostrum

Frequently Asked Questions

You can tell your baby is getting enough colostrum by observing their behavior and diaper output. Signs include frequent swallowing sounds during feeding, appearing content and sleepy after a feed, and producing wet diapers and transitioning their stool color from black meconium to yellow.

No, not everyone notices or leaks colostrum during pregnancy, and this is completely normal. The body produces it for the baby after birth, regardless of whether any leakage was visible before delivery.

Colostrum production doesn't stop abruptly but rather gradually transitions. Around three to five days after birth, your milk will start to 'come in,' becoming more voluminous and changing composition. Small amounts of colostrum may remain in your milk for several weeks.

Colostrum is vital for newborns because it is packed with antibodies and nutrients that protect against infection, helps establish a healthy gut lining, and acts as a laxative to aid in passing meconium, which reduces the risk of jaundice.

If your mature milk is delayed, continuing to breastfeed frequently and have skin-to-skin contact is crucial. You can also hand-express colostrum to stimulate supply and ensure your baby receives some nutrition. Factors like a C-section or stress can cause delays, so patience and seeking lactation support are key.

Yes, colostrum can appear in a variety of colors, including clear, white, or creamy. While it is most famously known for its rich golden or yellow hue, any of these colors are normal and indicate healthy colostrum production.

While it is possible to pump colostrum, hand expression is often more effective, especially in the first few days. The thick consistency and small volume of colostrum can make it difficult for pumps to collect effectively.