Stretch marks seem to be caused by a stretching of the skin. Their severity is affected by several factors, including your genetic tendency, degree of stress on the skin and cortisone level. Cortisone — a hormone produced by the adrenal glands — weakens elastic fibers in the skin.
The skin consists of three key layers. Stretch marks form in the dermis, or middle layer, when the connective tissue is stretched beyond the limits of its elasticity. This is normally due to rapid expansion or contraction of the skin.
As the body grows, the connecting fibers in the dermis slowly stretch to accommodate slow growth. However, rapid growth leads to sudden stretching. This causes the dermis to tear, allowing deeper layers of skin to show through.
This can form stretch marks and contributes to the way they look.
Stretch marks eventually fade to a silvery, white, or glossy appearance, due to the pale fat beneath the skin becoming visible instead of the usual blood vessels.
They are more likely to develop and become more severe where there are high levels of circulating cortisone, or when cortisone is applied to the skin. Cortisol, the stress hormone produced by the adrenal glands, is converted into cortisone. This weakens elastic fibers in the skin.
Anyone can develop stretch marks, but some factors increase your likelihood of getting them, including:
The best way to reduce the likelihood of getting stretch marks is to maintain a healthy weight. During pregnancy you'll gain weight over a relatively brief period. Work with your doctor to avoid gaining too much by eating well and exercising. This not only minimizes stretch marks but also is healthy for you and your baby.