It's called the linea nigra, or 'black line', and according to Cleveland Clinic, it can be defined as a dark vertical line ...

Physiologic changes in skin Pre-existing conditions that change with pregnancy Specific changes that are directly related to the condition of pregnancy Linea nigra means “black line” in Latin ...

Take a look at the Prada Linea Rossa Collision Technical Fabric sneaker in the gallery above in black, white, and “Steel Gray,” and purchase all three colorways on Prada’s website now.