Skip to main content
An official website of the United States government
Español
Government Funding Lapse
Because of a lapse in government funding, the information on this website may not be up to date, transactions submitted via the website may not be processed, and the agency may not be able to respond to inquiries until appropriations are enacted.

The NIH Clinical Center (the research hospital of NIH) is open. For more details about its operating status, please visit cc.nih.gov.

Updates regarding government operating status and resumption of normal operations can be found at opm.gov.

lactation

(lak-TAY-shun)
The process of making and secreting milk from the mammary glands in the breasts. Lactation usually begins during pregnancy when changes in certain hormones signal the mammary glands to make milk. After a person gives birth, the nipples release milk when a baby feeds from the breasts or when the person uses a breast pump. Lactation usually continues until milk is no longer being taken from the breasts. Lactation can sometimes be induced using certain hormone medicines in people who are not pregnant. Common factors that can affect lactation include hormone levels, certain medical conditions, breast surgery, injury to the breast or nipple, drug or alcohol use, and taking certain medicines.
Search NCI's Dictionary of Cancer Terms