Abstract

Breast cancer is a common type of cancer diagnosed during pregnancy, and its incidence has increased in recent years as more women choose to delay childbirth. Compared with breast cancer in the general population, pregnancy-associated breast cancer (PABC) is significantly different in terms of epidemiology, diagnosis, and treatment management, yet exhibits particularly aggressive behavior due to its unique molecular and biological profile.Although not fully understood, the pathophysiological basis of PABC may result from a combination of hormonal and immunological changes, breast regression, and gene expression changes during pregnancy. There is considerable controversy in the existing literature regarding the impact of PABC on pregnancy outcomes, both in terms of short-term and long-term effects on maternal and fetal/neonatal health. The majority of patients with PABC have advanced disease when first diagnosed, poor survival, and a significantly poor prognosis. Although the most commonly reported obstetricfetal adverse events are prematurity and prematurity-related neonatal morbidity, other treatment-related neonatal complications are common even when safe treatment options are used during pregnancy. The aim of the current comprehensive review is to summarize current knowledge and understanding of the pathophysiological, molecular, and biological basis of PABC and its association with adverse maternal, obstetric, fetal, and neonatal outcomes.