60 to 80% of women will have stretch marks during pregnancy. Primiparas but also young women will be most often affected. However, the number of pregnancies does not influence the appearance of new stretch marks, which often appear surreptitiously between the 6th and 9th month. These stretch marks have a dual origin: mechanical and hormonal.

What are stretch marks?

Stretch marks are defined as skin bands with a scar-like appearance due to damage to the elastic and collagen fibers of the dermis. They appear in the form of a linear atrophic lesion, flexible, purplish-red in color at first, then pearly and finally scarred. The dermis no longer supports the epidermis correctly, which appears wrinkled. At their level, we find neither hair, nor sebaceous or sweat secretion. Generally multiple, they are grouped together in a bundle of parallel lines along the cutaneous cleavage lines and often adopt a symmetrical arrangement.

Elastic fibers play a major role in the formation of stretch marks. Indeed, they present an abnormal, fragmented ultrastructure, where their density is higher than normal. Elastic fibers acquire a similar appearance as they age. Collagen fibers are arranged parallel to the skin surface and are oriented perpendicular to the axis of the stretch mark, thus in the direction of the mechanical stress to which the skin is subjected.

Changes in the size, number and arrangement of collagen fibers would correspond to a biological response to the mechanical stress caused on the skin by the tension of the underlying muscle.

At the cellular level, fibroblasts are modified within stretch marks; they present a globular rather than stellar shape. They are inactive and lose all signs of fibrillary secretion. In recent stretch marks, the fibroblasts acquire a more contractile character corresponding to that of old fibroblasts. This is a reaction process to excessive stretching of the skin and underlying tissue. This process becomes inactive over time, when the lesions take on a scar-like appearance.

Intervening on stretch marks with Winback

Stretch mark evolution occurs in two phases:

• The inflammatory phase: the stretch mark is erythemato-violet due to the presence of numerous capillaries. At this stage, pruritus may be felt.

• The scarring phase: the atrophy begins in the center and spreads towards the edges, creating a palpable depression with an impression of emptiness. The stretch mark then gradually turns pink and then turns pearly white.

Winback, by its well-known action on fibroblast, allows us to intervene on the two phases of stretch marks in different ways. During the inflammatory phase, we will work in athermia in order to avoid the inflammatory rebound. The biological action will be beneficial to relaunch the fibrillar secretion of the fibroblasts. On the other side, the deep action of DEEPCET will allow the relaxation of the underlying muscle, thus reducing the mechanical stress on the dermis. During the scarring phase, the objective will be to boost fibroblast neocollagenesis to reduce the impression of vacuity. Hyperthermia will then be sought either with the CET, or with MIX 3 face or MIX 3 body.