According to the resarch, published in the British Journal of Dermatology, skin stretching is not the only risk factor and while further learning is needed, it means current treatments are not based on solid scientific research, according to study author Frank Wang, M.D., assistant professor and dermatologist at the University of Michigan Health System.
Striae gravidarum, or ‘stretch marks’ of pregnancy, begin as erythematous streaks, and mature over months to years to become permanent scar-like bands that may be hypo-pigmented, atrophic and lax.
"Because stretch marks may compound the stress of new motherhood for many women, it's important to learn more about them," says Wang.
"Some women feel like their self-esteem, quality of life and willingness to engage in certain activities are affected."
Stretch marks affect 50-90% of women, with some at higher risk than others, due to factors like family history, weight gain, single or multiple birth; and the area hasn't received much research attention because they're not viewed as medically dangerous.
‘More complicated…’
Wang states that very few to none of the items on the market at present touted to prevent or fix stretch marks really work, and so his team investigated what could be causing stretch marks at the molecular level.
To do this, they focused on investigating the dermal elastic fibre network, which provides human skin with elastic properties.
In the research, the team studied skin samples from 27 pregnant women who had recently-formed stretch marks, comparing the stretch mark skin to both nearby stretched skin on the abdomen and to less-stretched skin on the hip.
The elastic fibre network was examined by Verhoeff elastic staining and immunofluorescence staining of skin sections. Gene expression was measured by real-time polymerase chain reaction.
The team found that the elastic fibre network in the dermis gets disrupted in a stretch mark, and this remains after giving birth.
The skin tries to repair the disrupted elastic network but it does not appear to be effective, which in turn promotes the lax, loose skin seen in more mature stretch marks.
"It may, therefore, make more sense to focus on preserving the elastic fibres you have rather than repairing damaged ones within stretch marks," adds Wang. "Regardless, it's more complicated than just rubbing something on your stomach."
Looking forward, Wang is already continuing his research with the end goal of helping pregnant women prevent or effectively improve the appearance of stretch marks. Another study in the works examines changes in collagen, which gives skin its strength and support, in stretch marks.