The human endometrium: atlases, models, and prospects.

Approximately every month, the human endometrium undergoes a cycle of proliferation, differentiation, and, in the absence of pregnancy, shedding and repair. Each cycle relies on intricate interorgan coordination of hormonal secretions. Endometrial dysfunction causes significant health complications, including abnormal menstrual bleeding and endometriosis. However, effective diagnosis and treatments are hampered by understudied aetiology. Recent single-cell profiling has disentangled the diverse and dynamic nature of the endometrium, revealing regulatory roles of WNT, NOTCH, and TGFβ signalling. These insights have informed mechanistic studies enabled by advanced in vitro models that capture endometrial cellular heterogeneity and structure. In this review, we outline key single-cell transcriptomics atlases and models that provided new avenues for studying endometrial biology, discuss their limitations, and propose future directions.