Most providers recommend starting colostrum harvesting at 36 to 37 weeks of pregnancy, though some people with specific medical needs may begin as early as 34 weeks under guidance. The timing depends on your health history, your pregnancy risk factors, and whether your provider has identified a reason to collect colostrum before your baby arrives.
The Standard Starting Window
For low-risk pregnancies, 36 to 37 weeks is the most widely recommended time to begin hand expressing colostrum. By this point, your body has been producing colostrum since the second trimester, and your pregnancy is far enough along that the small amount of oxytocin released during hand expression poses essentially no risk of triggering early labor.
A randomized controlled trial published in Maternal Health, Neonatology and Perinatology tested whether starting even earlier, at 34 weeks, was safe in healthy first-time mothers. The study found no difference in gestational age at birth between women who expressed and those who didn’t, and no adverse events were reported. Still, most hospital guidelines stick with 36 to 37 weeks as the default starting point for people without a specific medical reason to begin sooner.
Who Benefits Most From Early Collection
Colostrum harvesting is especially encouraged for people with gestational or pre-existing diabetes. Babies born to mothers with diabetes are at higher risk of low blood sugar after birth, and having a small supply of colostrum on hand means the baby can be fed immediately without needing formula or IV fluids. Research comparing colostrum to formula for glucose stabilization in newborns of diabetic mothers found no difference in blood sugar values between the two groups. After hospitals adopted colostrum-first protocols, NICU admissions for blood sugar issues decreased and exclusive breastfeeding rates went up.
Beyond diabetes, providers may also suggest harvesting if you have a planned cesarean birth, are expecting a baby with a known health condition like a cleft palate or heart defect, are carrying multiples, or have a history of low milk supply. In these situations, having even a few milliliters of frozen colostrum can bridge the gap between birth and when breastfeeding is fully established.
When You Should Not Harvest
Certain pregnancy complications make colostrum expression unsafe. You should not attempt it if you have:
- Reduced fetal movements or any vaginal bleeding
- A history of preterm labor or threatened preterm labor
- Cervical insufficiency or a cervical stitch in place
- Placenta previa
- A multiple pregnancy (unless your provider specifically approves it)
Certain medications, including some anti-epileptic drugs and antidepressants, can also pass into colostrum and make harvesting inadvisable. If any of these apply to you, check with a lactation consultant or your maternity provider before expressing.
How Much You Can Expect to Collect
The volumes are tiny, and that’s completely normal. In the days around birth, colostrum production averages about 5 milliliters per session on the first day and gradually increases to around 20 to 25 milliliters per session by day three. During pregnancy, you’ll likely collect even less, sometimes just a few drops per session. This can feel discouraging, but a newborn’s stomach is roughly the size of a marble. Those drops matter more than they look.
Don’t judge success by volume. Even half a milliliter per session is worth saving. Over a week or two of daily practice, small amounts add up, and having any colostrum available at birth gives your baby a head start.
How to Do It and How Often
Colostrum is harvested by hand expression, not with a breast pump. Pumps aren’t effective at extracting the thick, sticky colostrum produced during pregnancy and in the first days after birth. The technique involves placing your thumb and forefinger about an inch behind the nipple, gently compressing the breast tissue in a rhythmic press-and-release motion, and catching the drops as they appear.
Most guidelines suggest expressing once or twice a day, for about five to ten minutes per breast. You can gradually increase to two or three short sessions daily as you get more comfortable with the technique. There’s no need to push yourself to long sessions. Frequency matters more than duration.
Storing What You Collect
You’ll need a few simple supplies: small oral syringes (1 mL or 3 mL sizes work well), a clean small cup or medicine cup to catch drops, resealable plastic bags, and labels with the date. Some hospitals offer colostrum collection kits at prenatal appointments.
After each session, draw the colostrum into a syringe using the plunger. You can add to the same syringe throughout the day, keeping it in the refrigerator between sessions. At the end of the day, label the syringe with the date, place it in a resealable bag, and move it to the freezer. Freshly expressed colostrum keeps for up to three days in the coldest part of the refrigerator. In a standard freezer with a separate door, it stays good for three months. In a deep freezer, it lasts up to six months.
When you pack your hospital bag, bring your frozen syringes in a small cooler with ice packs. Many hospitals ask that you limit what you bring to about 15 syringes, so plan accordingly if you’ve been collecting for several weeks.
The Effect on Your Postpartum Supply
One of the less obvious benefits of prenatal hand expression is what it does for milk production after birth. A study comparing women who practiced daily antenatal expression after 37 weeks with women who did not found striking differences. Among those who expressed during pregnancy, 94% had established full milk flow within 30 minutes of their first breastfeed after birth, compared to 70% in the group that hadn’t practiced. The difference was statistically significant, and researchers concluded that antenatal expression reduced breastfeeding failures overall.
This makes sense intuitively. Hand expression during pregnancy familiarizes you with the technique, stimulates the breast tissue, and gives you confidence before the high-pressure early days with a newborn. Even if your primary goal is to stockpile a few syringes, the practice itself pays dividends once your baby arrives.