Uterine Junctional Zone and Its Relation to Adverse Obstetrical Outcomes in Assisted Reproductive Technology

The junctional zone (JZ) is an internal layer of the myometrium, with unique characteristics that allow its visualization as a hypoechogenic structure in three-dimensional (3D) ultrasound. While there is a growing realization that the origins of major obstetrical complications associated with defective deep placentation, such as pre-term labour, fetal growth restriction and pre-eclampsia, may lie in the very early pregnancy events, the underlying mechanisms are not understood.