Pumping while pregnant refers to the deliberate stimulation of the breasts, usually with a pump or by hand expression, to collect colostrum before delivery. This practice, often called antenatal expression, requires careful consideration of the physiological effects it has on the pregnant body. For low-risk pregnancies, this activity is generally considered acceptable in the later stages, but it carries safety implications related to uterine activity.
The Hormonal Link Between Nipple Stimulation and Uterine Activity
The primary concern with breast or nipple stimulation during pregnancy centers on the release of a hormone called oxytocin. This hormone is naturally produced by the hypothalamus and released by the posterior pituitary gland in response to sensory input, such as touch or suckling on the nipple. Oxytocin is widely known for its dual function in the body, which includes both the milk ejection reflex and stimulating the smooth muscle of the uterus.
Upon stimulation, nerve signals travel from the breast to the brain, prompting a release of oxytocin into the bloodstream. This surge of oxytocin travels to the uterus, which has become increasingly sensitive to the hormone as pregnancy advances. The hormone then binds to receptors in the uterine muscle, triggering contractions.
These contractions are the same type that initiate labor, which is why nipple stimulation is sometimes suggested as a natural way to encourage labor onset in full-term pregnancies. The release of oxytocin from nipple stimulation is often described as pulsatile, or in short bursts. Any activity that causes uterine contractions must be approached with medical guidance to avoid the risk of preterm labor.
Safety Guidelines and High-Risk Situations
Consultation with a healthcare provider is a necessary step before attempting any form of antenatal expression or pumping. The primary safety concern is the potential for oxytocin-induced contractions to trigger labor before the pregnancy is considered full-term. This practice is generally advised only for low-risk pregnancies and typically not before 36 or 37 weeks of gestation.
The practice is strictly contraindicated in pregnancies classified as high-risk due to specific complications that could be worsened by uterine contractions. These high-risk scenarios include having a history of preterm labor in a previous pregnancy or a diagnosis of an incompetent cervix. Conditions such as placenta previa, where the placenta covers the cervix, also make nipple stimulation unsafe because contractions could lead to severe bleeding.
Other contraindications include carrying multiples and preeclampsia. For individuals cleared to try antenatal expression, safety protocols involve limiting the duration of stimulation, often to short intervals like five to ten minutes per breast, and keeping the frequency low. Stop immediately if any painful or regular contractions are felt, or if any bleeding or unusual discomfort occurs.
Antenatal Colostrum Expression
The most common and medically supported reason for pumping while pregnant is the purposeful collection of colostrum before the baby arrives. Colostrum, the first milk produced, is rich in antibodies and nutrients, serving as the perfect first food for a newborn. Harvesting this milk antenatally provides a freezer stash that can be used if the newborn has difficulty feeding immediately after birth or requires supplementation.
This proactive step is particularly beneficial for mothers diagnosed with gestational or pre-existing diabetes, as their newborns are at an elevated risk for low blood sugar levels after delivery. Having the mother’s own colostrum available helps stabilize the baby’s glucose levels without needing to rely on formula. Antenatal expression also helps mothers become familiar with milk collection, easing the transition to feeding after birth.
When performing this expression, medical experts frequently recommend using gentle hand expression rather than an electric pump. Colostrum is thick and produced in very small amounts, often measured in drops or milliliters, which can be easily lost in the tubing and parts of an electric pump. Hand expression allows for the collection of these small, concentrated amounts directly into a sterile syringe for freezing and later use.