Don't believe the hype when you see
those creams and ointments promising
to prevent or reduce pregnancy stretch
marks. Dermatologists are still learning
about what causes stretch marks in the
first place, and skin stretching is not
the only risk factor.
Not medically dangerous
"Most of the existing products aren't
based on solid scientific research," said
Frank Wang, M.D., assistant professor
and dermatologist at the University of
Michigan Health System. "Very few to
none of the items touted to prevent or
fix stretch marks really work."
For a new study in the British Journal of
Dermatology, Wang's team investigated
what could be causing stretch marks at
the molecular level.
Wang has spent more than eight years
studying stretch marks, a field that
hasn't received much research
attention because they're not viewed
as medically dangerous.
"Because stretch marks may compound
the stress of new motherhood for
many women, it's important to learn
more about them," Wang said. "Some
women feel like their self-esteem,
quality of life and willingness to engage
in certain activities are affected."
The line-shaped lesions also known as
striae gravidarum affect 50 percent to
90 percent of women. However, some
women are at higher risk than others,
due to factors like family history, how
much weight they gain in pregnancy,
whether it's a single or multiple birth
and whether they've had stretch marks
before for another reason like obesity.
Researchers 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.
Changes in collagen
Wang and his colleagues found the
elastic fibre network in the dermis gets
disrupted in a stretch mark. After
giving birth, this network remains
disrupted. Elastic fibres give skin its
elasticity, or the ability to "snap back",
after stretching. 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.
Unfortunately, present research of
topical treatment options doesn't find
anything currently available to
effectively repair those disrupted
elastic fibres. "It may, therefore, make
more sense to focus on preserving the
elastic fibres you have rather than
repairing damaged ones within stretch
marks," Wang said. "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 in stretch marks. Collagen is
what gives skin its strength and
support.
Wang's team is also studying changes in
more established stretch marks that
have become less visible, and finishing
a survey study of about 200 pregnant
women to learn more about the effect
on quality of life.
The authors see the potential for
expanding this knowledge to other
reasons people get stretch marks, such
as obesity, growth spurts or steroid
usage.
