Can Stretch Marks be Prevented?
Kelsey McLaughlin, PhD
What are stretch marks?
Clinically known as striae gravidarum, stretch marks are fine bands that can appear on the skin during pregnancy. Stretch marks typically appear later in pregnancy as the baby grows. These marks look different on every woman, but typically begin as flat red or violet bands that then fade to a pale or skin color. Common areas for stretch mark development include the abdomen, breasts, buttocks and thighs.
It is not known exactly how common stretch marks are in pregnant women. Some studies report that as many as 90% of pregnant women develop stretch marks. Although stretch marks are commonly thought of as a physical concern, they can cause psychological discomfort that impacts quality of life.
What is happening to my skin...
Stretch marks appear in areas of the body where connecting fibres in the dermal layer of the skin stretch. The dermis is the thick middle layer of the skin that contains nerve endings, sweat glands, hair follicles and blood vessels. The dermal layer lies between the tough outer portion of the skin (the epidermis) and the inner fat layer that insulates and protects the body.
The cause of stretch marks during pregnancy is not exactly clear. Stretch marks are clearly a disruption and disorganization of skin components, including elastin and collagen. These abnormalities may reduce the strength and elasticity of the skin. Scientists have hypothesized that stretch marks are caused by a combination of genetics, pregnancy-related hormones and stress on the layers of the skin during pregnancy.
Unfortunately, research investigating the exact causes of stretch marks has been limited and inconsistent.
What are the risk factors for stretch marks?
Scientists have identified risk factors for the development of stretch marks during pregnancy. A study published in 2015 evaluating 800 pregnant women determined that a number of clinical and social factors were associated with a higher risk of developing stretch marks. These risk factors included:
Maternal factors: younger maternal age, higher pre-pregnancy weight, skin type or lighter skin tone
Pregnancy factors: higher maternal weight at delivery, higher baby birth weight
Family history of stretch marks
Interestingly, maternal socioeconomic status (eg. absence of employment, lower education level) is also related to stretch mark development during pregnancy. This is most likely a complex web relating to underlying maternal health.
Can stretch marks be prevented?
A recent study found that over 70% of pregnant women used a product to prevent or reduce the development of stretch marks.
Do any of these products actually work?
Let’s think back to what causes stretch marks and what are risk factors for stretch marks. There are some risk factors that are can be changed, such as maternal weight. However, the majority of stretch mark risk factors cannot be altered.
Topical treatments (applied to the skin) have not shown great efficacy for the prevention of stretch marks. A 2012 Cochrane review determined that there is no high-quality evidence to show that topical preparations with active ingredients are effective in preventing the development of stretch marks during pregnancy, or reducing how severe they are.
Let’s talk about Bio-Oil® specifically for a moment. Bio-Oil® is the most frequently used product for stretch mark prevention, with over 60% of pregnant women utilizing this product. Bio-Oil® claims that ‘keeping the skin moisturized and ensuring the skin maintains its maximum elasticity is the body's best defense against the formation of stretch marks’ through a ‘formulation that combines vitamins, plant extracts, and oils’ . However, there have been few trials to scientifically evaluate the efficacy of Bio-Oil® in this capacity. A study in 2009 reported that Bio-Oil® improved the appearance of stretch marks in 20 pregnant women. An additional study determined that Bio-Oil® significantly improved the appearance of stretch marks in non-pregnant females. However, this study is not published in an academic journal so the full details are not available for analysis, and should therefore be interpreted with caution.
Creams containing the plant extract Centella asiatica, also known as Gotu kola, have demonstrated some effectiveness for stretch mark prevention. A double-blind trial published in 1991 determined that a cream with Centella asiatica significantly reduced the development of stretch marks from 56% to 34% in 80 pregnant women. Another double-blind trial published in 2012 reported that a cream containing the Centella asiatica extract reduced the incidence of stretch mark development in pregnant women and reduced the ‘severity’ of stretch marks. However, there is little information regarding the safety of this extract during for pregnant or nursing women.
Olive oil is a common topical treatment used for stretch mark prevention. A 2011 trial determined that the application of olive oil twice a day from 18 weeks' gestation did not reduce stretch mark development. However, other studies have reported that olive oil does reduce the development of stretch marks, indicating that more research is needed to provide a definitive answer.
Almond oil has also been investigated for the prevention of stretch marks. An interesting trial published in 2012 reported that the use of almond oil alone did not prevent stretch marks in first-time pregnant women compared to pregnant women who did not apply almond oil. However, when almond oil was applied with massage, stretch marks development was lower than women who didn't use massage. Scientists hypothesized that the benefit of stretch mark reduction may be due to the massaging action alone, rather than the almond oil treatment itself.
Similarly, cocoa butter does not reduce the development of stretch marks in pregnant women. Products containing hyaluronic acid have also been investigated for stretch mark prevention, however, there are no recent trials providing evidence.
Stretch marks are a common development during pregnancy, with risk factors that include maternal factors, pregnancy factors and family history of stretch marks. Most pregnant women report using a topical treatment to help prevent the development of stretch marks. However, there is limited evidence that topical treatments are effective for stretch mark prevention.
Every woman and every pregnancy is unique. Pregnant women should speak to their healthcare provider to ensure maternal and fetal safety. This article is meant to provide readers with current information and opinions. All medical and treatment decisions should be discussed with your healthcare provider.