Most pregnant people can safely begin collecting colostrum at around 36 weeks of gestation. Before that point, breast stimulation carries a theoretical risk of triggering contractions, so earlier collection is generally only recommended under direct guidance from a healthcare provider. Starting at 36 weeks gives you roughly four weeks to build a small supply before your baby arrives.
Why 36 Weeks Is the Standard Starting Point
Hand expressing colostrum during pregnancy, sometimes called antenatal colostrum expression, involves gently massaging the breast to draw out the thick, nutrient-rich milk your body starts producing well before delivery. Your breasts may begin making colostrum as early as the second trimester, but that doesn’t mean you should start collecting it right away.
The concern with earlier expression centers on oxytocin, the same hormone that drives labor contractions. Breast stimulation triggers a small release of oxytocin, which raises a theoretical risk of preterm labor. Clinical trials, including the large Diabetes and Antenatal Milk Expressing (DAME) trial in Australia, have confirmed that expression starting around 36 weeks does not increase preterm birth rates in low-risk pregnancies. By 36 weeks, your baby is developed enough that even if labor were to start slightly early, the risks are minimal.
Who Benefits Most From Early Collection
Colostrum collection is especially useful if your baby has a higher chance of needing supplemental feeding in the first hours after birth. The most common scenario is gestational or pre-existing diabetes. Babies born to mothers with diabetes are more prone to low blood sugar (neonatal hypoglycemia) right after delivery and often need supplemental feeds to stabilize. Research has shown that newborns fed colostrum rather than formula in these early feeds are less likely to develop hypoglycemia, partly because colostrum’s protein content helps stabilize blood sugar without spiking the baby’s own insulin production the way formula can.
Other situations where having a frozen stash of colostrum proves valuable include expected preterm delivery, planned cesarean section, known conditions like cleft lip or palate that can make latching difficult, and any circumstance where you and your baby might be separated after birth. Even for uncomplicated pregnancies, having a small reserve can ease stress during the first days of breastfeeding.
When You Should Wait or Avoid It
Not everyone should express colostrum before delivery. If you have a history of preterm labor, cervical insufficiency, placenta previa, or have been told you’re at risk of early delivery, the small oxytocin release from breast stimulation may not be worth the risk. Some observational studies have noted that mothers with diabetes who express antenatally may have slightly higher rates of neonatal intensive care admission, though the controlled trials haven’t confirmed a direct cause. If you fall into any higher-risk category, talk to your midwife or obstetrician before starting.
How Much to Expect
Colostrum comes in very small volumes, and that’s completely normal. In the first sessions during pregnancy, you may get only a few drops. Don’t interpret tiny amounts as a sign of low supply. Even after birth, the typical volume on day one is about 5 milliliters per expression session (roughly one teaspoon). By day three postpartum, that climbs to around 20 to 25 milliliters per session. Your baby’s stomach is only marble-sized at birth, so these small quantities are exactly what they need.
During antenatal collection at 36 to 40 weeks, expect even less than those postpartum numbers. Collecting a few milliliters across an entire day is a good result. Over several weeks of consistent practice, you can accumulate a meaningful reserve stored in small syringes in your freezer.
How to Express and Collect
Hand expression works better than a pump for colostrum because the volumes are too small for most breast pumps to capture effectively. La Leche League recommends starting with 3 to 5 minutes of expression on each breast, two to three times per day, making sure each breast gets expressed at least twice. A warm shower or a warm cloth on your breasts beforehand can help get things flowing.
To collect, use small oral syringes rather than bottles. Colostrum collection kits typically include 0.5 or 1 milliliter syringes designed for the tiny amounts you’ll produce. You can express directly onto a clean spoon or small container and then draw the colostrum into the syringe. Cap each syringe, label it with the date, and freeze it. Some people find it helpful to collect from multiple sessions on the same day into one syringe before freezing.
Storing Colostrum Safely
The CDC’s breast milk storage guidelines apply to colostrum as well. Freshly expressed colostrum stays safe at room temperature (77°F or cooler) for up to 4 hours, in the refrigerator for up to 4 days, and in the freezer for about 6 months at best quality, though up to 12 months is acceptable. For antenatal collection, freezing is the practical choice since you’re building a supply over weeks.
Store your labeled syringes in a sealed freezer bag so they’re easy to grab when you head to the hospital. Bring them in a small cooler with ice packs. Most birth centers and hospitals can store them in a freezer on arrival and thaw individual syringes as your baby needs them, typically by holding the syringe under warm running water.
What the First Sessions Feel Like
Your first few attempts may produce nothing visible, and that’s fine. The technique takes practice. Place your thumb and forefinger about an inch behind the nipple, press gently back toward your chest wall, then compress and release in a rhythmic motion. Avoid squeezing the nipple itself. You may notice a yellowish, sticky substance appearing at the nipple after a minute or two. Some people see results on the first try, while others need several days of practice before colostrum appears.
If you experience any cramping, tightening, or contractions during expression, stop the session. Occasional mild tightening (Braxton Hicks contractions) can happen and usually passes quickly, but regular or painful contractions are a signal to stop and check in with your provider before continuing. For most people at 36 weeks and beyond, these sessions feel uneventful and become a simple part of the daily routine leading up to birth.