Antenatal expression, often called colostrum harvesting, is the process of gently collecting small amounts of breast milk before the baby is born. This initial milk, known as colostrum, is rich in antibodies and nutrients, making it highly beneficial for a newborn, especially one facing early challenges. The timing of when a pregnant woman can begin this practice is a significant consideration for maternal and fetal well-being. Starting expression prematurely risks stimulating the uterus, so medical guidance on the appropriate gestational week is paramount.
The Critical Timing for Antenatal Expression
For a pregnant woman with an uncomplicated, low-risk pregnancy, the standard recommendation is to begin antenatal expression no earlier than 36 or 37 weeks of gestation. This timeline is established because nipple stimulation triggers the release of oxytocin, the hormone responsible for causing uterine contractions and initiating labor.
Beginning expression before this late-term window carries a theoretical but acknowledged risk of stimulating premature labor in vulnerable individuals. By waiting until the final weeks of pregnancy, a woman is considered to be at term or near-term, where a mild increase in uterine activity would not pose the same threat to the fetus. Even after 36 weeks, it is generally advised to start slowly, perhaps expressing for only a few minutes, one or two times daily, to monitor the body’s reaction.
Medical and Practical Reasons for Early Pumping
While many express to practice the skill, certain clinical scenarios make stored colostrum particularly valuable. The most common reason is the presence of gestational or pre-existing diabetes, which increases the newborn’s risk of low blood sugar (hypoglycemia) after birth. Having expressed colostrum available allows the baby to receive mother’s milk to stabilize blood glucose instead of needing formula supplementation.
Antenatal collection is also encouraged when mother and infant separation is anticipated, such as during a planned cesarean section or if the baby needs special care in the neonatal unit. Furthermore, infants born with congenital conditions like a cleft lip or palate, or those diagnosed with Down syndrome, may face immediate feeding difficulties. For these babies, a colostrum supply provides nutrition and immunological support. Mothers who have a history of previous breastfeeding challenges or structural breast anomalies, such as breast hypoplasia, may also benefit from the practice gained from early expression.
Essential Safety Precautions and Contraindications
Any decision to begin expressing before birth must be made in consultation with a healthcare provider, as certain conditions are considered absolute contraindications. Pregnant women with a history of preterm labor in previous pregnancies should not attempt antenatal expression. Any condition that predisposes a woman to early delivery, such as a short cervix or the presence of a cervical suture, also makes the practice unsafe.
Contraindications also include antepartum hemorrhage, such as unexplained vaginal bleeding, or a diagnosed placenta previa, where the placenta covers the cervix. If a woman begins expressing and experiences painful or painless uterine contractions, or notices any vaginal bleeding, she must stop immediately and seek medical advice. These signs indicate that uterine stimulation may be having an adverse effect.
Techniques for Expression and Colostrum Storage
Due to the small volume and thick consistency of colostrum, manual hand expression is the preferred method over using a breast pump during pregnancy. Hand expression ensures that no drops are lost to the plastic tubing or components of a machine. To begin, a mother should wash her hands thoroughly and apply a warm compress to the breast, which helps encourage milk flow.
The technique involves forming a “C” shape with the thumb and forefinger a few centimeters behind the areola. Gently compress the breast tissue toward the chest wall. Colostrum should be collected directly into sterile, small-volume containers, such as 1-milliliter or 3-milliliter syringes, which are ideal for the small amounts collected. Expressing for short durations, typically three to five minutes on each breast, two or three times a day, is usually sufficient.
Colostrum collected throughout the day can be added to the same sterile syringe, which should be stored in the refrigerator between collection sessions. At the end of the day, the syringe should be sealed, labeled with the date and time of collection, and transferred to the freezer. Frozen colostrum can be stored for up to six months. When labor begins, the frozen supply should be transported to the hospital in an insulated cooler bag with ice packs.