Pregnancy brings so many changes to your body, and one of the most exciting (and sometimes surprising) signs is when you first notice a little leakage from your breasts. That early breast milk is called colostrum, and many women wonder when does colostrum start leaking and what it means for their pregnancy and baby.
At Prime Hospital Panipat, our obstetrics and gynecology team answers this question frequently. Colostrum is not just “leakage”—it’s nature’s first, nutrient-packed milk, designed specifically for your newborn’s needs in the first few days of life. Knowing when and why it appears helps you feel more prepared and confident.
In this detailed guide, we’ll cover when colostrum production begins, when leaking typically starts, what it looks like, why some women notice it earlier or later, what to do if it starts leaking, when to worry, and how it transitions to mature breast milk after delivery.
When Does Colostrum Start Leaking? Typical Timeline During Pregnancy
Colostrum production actually begins much earlier than most people realize, but visible leaking varies widely.
Production starts:
- As early as 16–20 weeks of pregnancy (second trimester), your breasts begin making colostrum. The milk ducts and alveoli (milk-producing glands) are developing under the influence of pregnancy hormones (progesterone, estrogen, prolactin, and human placental lactogen).
- Most women do not notice anything at this stage because the amount is very small and stays inside the breast.
First visible signs / leaking:
- Second trimester (weeks 16–27): Some women notice small amounts of colostrum leaking, especially when breasts are stimulated (during sex, shower, or breast exam). It’s usually just a few drops, often only on one side at first.
- Third trimester (weeks 28–40): Leaking becomes more common—around 30–50% of women notice some colostrum by the third trimester. It may appear as crusty yellow spots on bra or nightclothes, or a few drops when you press the nipple.
- Average onset of noticeable leaking: Between weeks 32–36 for most first-time mothers. Multiparous women (those who’ve had previous pregnancies) often notice it earlier because their breasts have already been through the process.
After birth:
- Colostrum is present in the breast from the beginning of labor or immediately after delivery.
- It’s produced in small amounts (teaspoons per day) for the first 2–5 days, perfectly matching a newborn’s tiny stomach capacity.
- Around day 3–5 postpartum, colostrum transitions to transitional milk, then mature milk by day 10–14.
Factors That Influence When Colostrum Starts Leaking
Every pregnancy is different. Here are the main reasons some women leak early while others don’t notice until after birth:
- Previous pregnancies — Breasts that have lactated before “remember” the process and often start producing and leaking earlier.
- Hormone sensitivity — Higher prolactin or placental hormone levels can trigger earlier production.
- Breast stimulation — Sexual activity, nipple play, or even tight clothing can cause leakage by stimulating prolactin release.
- Breast size and structure — Women with larger breasts or more glandular tissue may notice leakage sooner.
- First vs. subsequent pregnancies — First-time mothers often don’t leak until late third trimester or after birth.
- Medical conditions — Rarely, conditions like pituitary tumors or certain medications can cause early leakage (galactorrhea), but this is uncommon in pregnancy.
What Colostrum Looks Like and Feels Like
Colostrum is very different from mature breast milk:
- Color: Thick, sticky, yellow, golden, clear, or slightly orange. Sometimes has tiny white flecks (early fat globules).
- Texture: Very thick and concentrated—more like honey or syrup than thin milk.
- Volume: Only drops to teaspoons per day during pregnancy and first few days postpartum.
- Taste: Slightly salty or sweet, very different from mature milk.
- Smell: Mild, sometimes described as slightly “eggy” or unique.
Many women first notice it as crusty yellow spots on their bra or nightdress in the morning.
Is Leaking Colostrum a Good Sign?
Yes—in most cases, leaking colostrum is a positive sign that your breasts are preparing for breastfeeding. It shows that prolactin levels are rising and milk-making tissue is developing normally.
However, no leaking during pregnancy is also completely normal—many women produce plenty of colostrum but don’t leak until after birth. Lack of leakage does not mean you won’t make milk.
When to See a Doctor About Colostrum or Breast Changes
Contact your obstetrician or gynecologist if:
- Leaking is bloody or green/brown (rare, but needs evaluation).
- You have severe breast pain, redness, or fever (possible infection/mastitis).
- Leaking starts very early (before 20 weeks) and is profuse (may need hormone check).
- One breast leaks significantly more than the other (asymmetry can be normal but should be checked).
- No breast changes at all by late third trimester and you’re worried about milk supply.
Preparing for Breastfeeding: What to Do When Colostrum Appears
- Wear breast pads (disposable or washable) in your bra to stay comfortable.
- Don’t try to express or pump colostrum during pregnancy unless medically advised (can stimulate contractions in some cases).
- Learn hand-expression technique—useful for collecting colostrum after birth if baby has feeding issues.
- Attend antenatal breastfeeding classes (most hospitals offer them).
Transition to Mature Milk After Delivery
After birth:
- Days 1–3: Colostrum only (thick, yellow, rich in antibodies and immune factors).
- Days 3–5: Milk “comes in” — breasts feel fuller, heavier; milk becomes whiter and thinner.
- Days 7–14: Mature milk fully established — higher volume, thinner consistency.
Frequent breastfeeding (or pumping) in the first week triggers this transition.
Conclusion: Leaking Colostrum Is Normal and a Sign Your Body Is Preparing
When does colostrum start leaking? Production begins as early as 16–20 weeks, but noticeable leaking usually starts in the third trimester (weeks 32–36 for most first-time mothers) or not until after birth. It’s a normal, healthy sign that your breasts are getting ready to feed your baby, and it does not mean anything is wrong if you don’t leak at all during pregnancy.
The appearance of colostrum—whether a few drops or crusty spots on your bra—is your body’s way of preparing for one of the most important jobs: nourishing your newborn. Embrace it as a positive milestone.
At Prime Hospital Panipat, our obstetricians and lactation consultants support you throughout pregnancy, delivery, and the early postpartum period. If you have questions about breast changes, colostrum, or breastfeeding preparation, reach out—we’re here to help you feel informed and confident.