Stretch marks (striae distensae) are a common skin condition, especially after pregnancy. While often associated with the later stages of gestation, noticing these linear streaks or their changing appearance postpartum is frequent. These marks represent dermal scarring resulting from significant changes to the skin’s structure. Understanding their formation and maturation helps manage their appearance.
The Biological Causes of Postpartum Stretch Marks
Stretch marks form when the skin stretches rapidly, causing structural damage in the dermis. This rapid expansion, particularly noticeable on the abdomen and breasts during pregnancy, physically strains the skin’s supportive network. The primary proteins responsible for elasticity and strength—collagen and elastin—are disrupted and begin to break down under this tension.
This stretching is compounded by significant hormonal influences during pregnancy. Elevated levels of glucocorticoids (like cortisol) and the hormone relaxin reduce the skin’s resilience. Glucocorticoids impair the function of fibroblasts, the cells producing collagen and elastin, further weakening the dermal structure. Relaxin, known for loosening ligaments and joints, may also affect the skin’s connective tissue.
As the skin stretches, the elastic fiber network is disrupted, leading to linear tears. The body attempts a repair process, but the resulting tissue is disorganized and lacks the proper arrangement of collagen and elastin fibers. This combination of physical stress and hormonal changes creates the environment where stretch marks develop, commonly showing up around the sixth or seventh month of pregnancy.
How Stretch Marks Change Postpartum
Many individuals feel they are getting stretch marks postpartum due to a change in their appearance, signifying maturation. Stretch marks initially appear as striae rubrae (red and pinkish marks) which can sometimes be slightly raised and itchy. This early color is due to inflammation and the presence of blood vessels close to the skin’s surface.
Over several months to years, these marks mature and transition into striae albae (white/silver marks). This color change indicates a reduction in inflammation and a loss of blood flow, meaning the mark has scarred over. At this stage, the stretch marks become chronic, appearing as linear, often depressed, atrophic scars with a wrinkled texture.
Postpartum, as the abdomen retracts and skin volume decreases, the mature white marks become more concentrated and noticeable. They are no longer obscured by the taut skin of pregnancy, which can give the impression that they are new. Since the damage to the dermal fiber network is fully established and inflammation has subsided, this mature stage is significantly more difficult to treat.
Treatment Options for Existing Stretch Marks
While complete removal of established stretch marks (striae albae) is often impossible, their appearance can be minimized. Treatment is generally more effective on newer, red marks. Topical treatments focus on ingredients that support collagen production and improve skin texture. For early-stage marks, prescription retinoids, such as tretinoin, can help rebuild collagen, though they must be avoided during pregnancy and breastfeeding.
Other topical ingredients, including hyaluronic acid and certain botanical extracts, can help improve skin hydration and elasticity, making the marks less obvious. However, scientific evidence supporting the efficacy of over-the-counter creams as a standalone treatment for established white marks is limited. Consistent massage and application on newer marks yield the most promising results.
For mature, white stretch marks, professional in-office procedures are required to stimulate dermal repair. Laser therapy, such as pulsed dye lasers, is effective on red marks by targeting blood vessels and reducing redness. For white marks, fractional lasers (like fractional CO2) and radiofrequency treatments create controlled micro-injuries in the dermis.
These controlled injuries trigger the body’s natural wound healing response, encouraging the production of new collagen and elastin fibers to remodel the scar tissue. Other procedures like microneedling and microdermabrasion work similarly by resurfacing the skin and stimulating collagen synthesis. Often, a combination of these treatments, sometimes including platelet-rich plasma (PRP), yields the most significant improvement in texture and appearance.