Most guidelines recommend starting to hand-express colostrum around 36 weeks of pregnancy, though your body actually begins producing it much earlier. Colostrum production starts around the midpoint of pregnancy, as early as 16 to 20 weeks, but actively expressing and collecting it before 36 weeks isn’t standard practice without guidance from your care provider.
When Your Body Starts Making Colostrum
Your breasts begin preparing for milk production surprisingly early. Around the 16th week of pregnancy, rising levels of estrogen and progesterone trigger changes in your breast tissue: milk ducts multiply and grow, the glands that will produce milk start developing, and your nipples and areolas darken and enlarge. By about 20 weeks, your body is already producing small amounts of colostrum.
This is the first stage of lactation, and it continues until a few days after birth. Some women notice colostrum leaking from their nipples during the second or third trimester. Others never leak at all. Neither situation says anything about how much milk you’ll eventually produce. The colostrum is there whether you can see it or not.
The 36-Week Recommendation
The standard guidance is to begin hand-expressing colostrum at or after 36 weeks of pregnancy, no more than twice a day, for no longer than 10 minutes per session. This timing balances two things: giving you enough time to build a small supply before birth, while keeping you well past the point where preterm birth is a concern.
Some research has tested earlier starting points. A pilot study of healthy first-time mothers who began hand expression at 34 weeks found no difference in gestational age at birth compared to women who didn’t express at all. No adverse events were reported, and no women experienced bleeding, contractions, or uterine pain during expression sessions. One participant noticed an increase in Braxton Hicks contractions a few days after starting, but these resolved on their own and she went on to deliver at full term.
Still, 36 weeks remains the most widely recommended starting point. If your provider suggests starting earlier based on your specific circumstances, that conversation is worth having, but don’t begin on your own before 36 weeks without checking first.
Why the Concern About Early Expression
The main worry has always been that nipple stimulation releases oxytocin, the same hormone used synthetically to induce labor. In theory, expressing colostrum could trigger contractions and lead to premature delivery. A Cochrane review of six trials involving 719 women past 37 weeks actually found that more women in the expression group went into labor compared to those who didn’t express, suggesting it could help nudge labor along at full term.
But at earlier gestational ages, the available evidence doesn’t support this fear. Studies comparing women who expressed before term to those who didn’t have consistently found no difference in when labor began. The oxytocin released during brief hand expression sessions appears to be far less than what’s needed to initiate labor in a healthy pregnancy.
Who Benefits Most From Antenatal Expression
Any pregnant person can choose to express colostrum in late pregnancy, but it’s particularly useful in situations where a newborn may need supplemental feeding right away. The most common reason is gestational diabetes or pre-existing diabetes. Babies born to mothers with diabetes are at higher risk of low blood sugar after birth and often need extra feeding in the first hours of life. Having a stash of frozen colostrum ready means you can supplement with your own milk instead of formula.
Other situations where having colostrum on hand can help include expecting a baby with a known heart condition or cleft palate, planning a cesarean birth (which can sometimes delay milk coming in), or having a history of low milk supply. If your baby ends up in the NICU, having expressed colostrum available from day one can make a real difference.
How Much to Expect
Colostrum comes in very small quantities, and that’s completely normal. During pregnancy, you may get only a few drops per session. Don’t let this discourage you. A newborn’s stomach on the first day of life holds roughly 5 milliliters, about one teaspoon. By day three, a typical feeding is around 20 to 25 milliliters. Colostrum is dense with antibodies and nutrients, so a little goes a long way.
Collect what you express using small syringes (1 mL or 3 mL sizes work well). You’ll likely fill fractions of a syringe at first. Over several sessions across the final weeks of pregnancy, these small amounts add up into a meaningful supply. Label each syringe with the date and freeze it. Bring your frozen syringes to the hospital in a cooler bag when you go in for delivery.
How to Hand-Express
Hand expression works better than a pump for colostrum because the volumes are so small that a pump can’t effectively collect them. Wash your hands, then place your thumb and forefinger about an inch behind your nipple, roughly at the edge of your areola. Press gently back toward your chest wall, then compress your fingers together in a rhythmic squeeze-and-release motion. Rotate your hand position around the breast to access different milk ducts.
Keep sessions to about 10 minutes total, covering both breasts. Twice a day is sufficient. You may get nothing the first few times, and that’s fine. The technique improves with practice, and your body responds more readily over time. A warm shower or warm cloth on the breast beforehand can help get things flowing. If you feel any cramping or tightening in your uterus during a session, stop and try again the next day.