This idiom is a euphemism for being pregnant, implying a woman is expecting a child, as if adding to the family. It conveys a delicate announcement or state, often used in personal or social contexts to describe pregnancy politely. The phrase carries a tone of discretion, joy, or formality, reflecting cultural values of modesty and the human tendency to soften sensitive topics. Its familial imagery evokes a warm, communal growth, resonating in scenarios like announcements or gossip. The idiom softens pregnancy’s mention, making it a genteel metaphor for expectant motherhood.

The phrase originated in 17th-century England, tied to Puritan modesty in discussing pregnancy, with early use in Samuel Pepys’ diary (1660s) for expectant women. Its modern form emerged in the 18th century, with Jane Austen’s *Sense and Sensibility* (1811) using it delicately. The idiom gained traction in 19th-century etiquette manuals, amplified by Victorian propriety and literature, notably in *The Times* (1900s) for society news. Its adoption across English-speaking cultures stems from its polite imagery and relevance to family life, especially in the U.K. and U.S.