Antenatal expression, or pumping during pregnancy, is the practice of collecting colostrum before the baby is born. The safety of this practice depends heavily on an individual’s specific medical history and the stage of pregnancy. It is generally not advised to start this process without first receiving clearance from a healthcare provider.
How Pumping Stimulates the Uterus
The primary concern regarding pumping or other forms of nipple stimulation during pregnancy is the potential for triggering uterine contractions. This effect is governed by the release of the hormone oxytocin. Stimulation of the breast and nipple area sends signals to the brain, prompting the pituitary gland to release oxytocin into the bloodstream.
Oxytocin has a dual function: it is responsible for the milk letdown reflex during feeding and stimulates the uterus to contract during labor. Stimulating the nipples can inadvertently initiate or intensify contractions. The uterus becomes increasingly sensitive to oxytocin as pregnancy progresses, which is why the risk of stimulation is generally considered lower near term.
Medical Safety Guidelines and Contraindications
For low-risk pregnancies, medical consensus advises against beginning antenatal expression before 36 or 37 weeks of gestation. This guideline minimizes the risk of inadvertently causing premature labor. Starting the process should always be a joint decision made in consultation with an obstetrician or midwife.
The practice is strictly forbidden for individuals with certain high-risk medical conditions, as the release of oxytocin could pose a significant danger. Absolute contraindications include:
- A history of preterm labor or having a short or incompetent cervix.
- Placenta previa, which involves the placenta partially or completely covering the cervix.
- A multiple gestation pregnancy, such as twins or triplets.
- Pre-eclampsia or pregnancy-induced hypertension.
- Any history of vaginal bleeding or threatened miscarriage during the current pregnancy.
If a medically cleared individual begins to feel painful or frequent contractions, or experiences any vaginal bleeding while expressing, they must stop immediately and contact their healthcare provider.
Reasons for Antenatal Colostrum Harvesting
If a pregnant person is determined to be low-risk and has medical approval, they may choose to express colostrum for several practical reasons. The main goal, known as colostrum harvesting, is to build a small supply of the nutrient-dense first milk. This stored supply serves as a crucial backup for the baby immediately after birth.
Colostrum is particularly beneficial for babies whose blood sugar levels may be difficult to stabilize, such as those born to mothers with pre-existing or gestational diabetes. A readily available supply of colostrum helps manage newborn hypoglycemia and potentially reduces the need for formula supplementation. Harvesting also benefits babies who may have difficulty latching initially, such as those with a cleft lip or palate.
The stored colostrum is also important if a baby is expected to be separated from the mother, such as due to an anticipated preterm birth or a planned Caesarean section. This ensures the baby receives the immunological and nutritional benefits of colostrum even if immediate skin-to-skin and direct feeding are not possible. For those who are cleared, hand expression is typically recommended over using a pump to start, with the colostrum collected directly into sterile syringes and stored in the freezer.