Final answer:
Sandberg discusses the preemptive career withdrawal by women anticipating family responsibilities, advising against holding back professional ambitions.
Step-by-step explanation:
The concept that Sandberg discusses in the chapter "Don't Leave Before You Leave" is about not mentally checking out of one's career before actually taking a break for life events such as maternity or paternity leave. Sandberg describes the dilemma associated with this behavior, which often involves women planning for family life well before they actually start a family. This anticipation leads them to not take on new projects or seek promotions, effectively setting back their careers prematurely. Sandberg warns that by doing so, women might hinder their professional growth and unintentionally narrow their opportunities. She urges individuals not to limit their ambitions based on future family plans and to continue pursuing their career goals until the moment they need to leave.