Breast milk sharing occurs both formally and informally.

On the formal side, many milk banks belong to the Human Milk Banking Association of North America (HMBANA), a voluntary professional association. HMBANA has policies for donor human milk collection that involve the rigorous screening of potential donors' health and medication use. Milk bank donors are also instructed on proper collection, storage and shipping — and their milk is pasteurized before it's distributed. Women who donate their breast milk in this way aren't paid. HMBANA milk banks provide milk for hospitalized infants and others who have a doctor's prescription.

Informal breast milk sharing practices also occur between friends, family and strangers online. Websites connecting people who want to sell and buy breast milk often include recommendations for buyers on how to minimize health and safety risks, such as making sure the donor has been screened for certain infections. However, breast milk shared by friends or bought through the internet is unlikely to have been collected, processed, tested or stored in a way that reduces risks to a baby. This kind of donated breast milk could contain:

• Bacterial growth and contamination with bacteria that could cause infection
• Infectious diseases, such as human immunodeficiency virus
• Chemical contaminants, such as prescription or illegal drugs
• Cow's milk, possibly due to the sellers' monetary incentive to boost the volume of their product

If, after talking to your health care provider, you choose to feed your baby breast milk other than your own, be cautious. The Food and Drug Administration recommends using milk only from a source that has screened its donors and taken other precautions to ensure the safety of the milk.