A proposed MRI classification of junctional zone morphology based on reproductive performance: the JZ-MRI ReproClass

We propose the junctional zone- magnetic resonance imaging (JZ-MRI) ReproClass, a four-tiered MRI-based classification for describing JZ morphology, developed from more than a decade of clinical experience in women with recurrent implantation failure or pregnancy loss despite normal embryo quality. The system characterises the spectrum of JZ appearances -from normal architecture to complete loss of differentiation- and is particularly informative when ultrasound and hysteroscopy appear normal. By standardising MRI assessment of the JZ, the ReproClass may help identify morphological patterns associated with impaired reproductive performance and support more individualised diagnostic reasoning. It provides a foundation for future research into the role of JZ architecture in fertility outcomes.