They occur exclusively in the third trimester due to rapid fetal growth, and their severity is unrelated to genetic or hormonal factors.

They develop due to the breakdown of elastin and collagen fibers in the dermis caused by mechanical stretching and hormonal influences.

Striae gravidarum are caused by autoimmune destruction of dermal tissue, commonly seen in women with preexisting autoimmune diseases.

Striae gravidarum result from increased collagen synthesis and thickening of the dermis due to elevated estrogen levels. making the skin more elastic.