Objective To evaluate and summarize the evidence of pregnancy guidance for young breast cancer patients,and provide the basis for medical staff to provide pregnancy guidance. Methods The guidelines,expert consensuses,evidence summaries,clinical decisions and systematic evaluations of pregnancy guidance of breast cancer patients were systematically searched from BMJ Best Practice,UpToDate,Cochrane Library,JBI,Pubmed, CINAHL,Embase,US National Guidelines Library,International Guidelines Collaborative Network,Scottish Intercollegiate Guidelines Ne...