I was about twenty-two weeks along when I noticed the first one. Not on my bump — which I'd been religiously moisturising since approximately the moment the test came back positive — but on my hip. A thin, pinkish-purple line about three centimetres long, slightly raised, vaguely shimmery in certain light. I stared at it in the bathroom mirror with the specific kind of dismay that comes from having done everything the internet told you to do and still not getting the result you were promised.
Because I had done everything. Bio-oil twice daily since week eight. Cocoa butter every evening. A cream marketed specifically for pregnancy stretch marks that cost £28 for a tube the size of a highlighter pen. I had been hydrated, moisturised, and devotionally oiled. And here was a stretch mark anyway, appearing on a part of my body I hadn't even thought to protect, as though my skin was making a point about the limits of consumer skincare.
This experience — and the subsequent research spiral it triggered — taught me something the beauty industry would prefer you didn't know: the science on stretch mark prevention is far less certain than the marketing suggests. Some things help. Some things do nothing. And the single biggest factor — genetics — is one you have absolutely no control over. So let's have the honest conversation about stretch marks during pregnancy: what they actually are, what the evidence says about preventing them, and why the conversation might benefit from less product and more perspective.
What stretch marks actually are (anatomy, not aesthetics)
Stretch marks — known medically as striae distensae, or striae gravidarum when they occur during pregnancy — are a form of scarring in the dermis, the middle layer of skin. They occur when skin stretches faster than the underlying connective tissue (specifically collagen and elastin fibres) can accommodate. The fibres tear, creating the visible lines on the skin's surface.
In their early stage (striae rubrae), stretch marks appear red, pink, or purple due to blood vessels showing through the damaged dermis. They may be slightly raised and can feel itchy as the skin stretches. Over time — typically months to years — they mature into striae albae: paler, flatter, sometimes silvery lines that are lighter than the surrounding skin. In darker skin tones, mature stretch marks may appear as slightly lighter or slightly darker lines, depending on the individual.
The most common locations during pregnancy:
- Abdomen: The most obvious area, where skin stretches the most dramatically. Stretch marks typically appear below the navel and radiate outward.
- Breasts: Breast tissue expands significantly during pregnancy (often by one or two cup sizes), and the skin over the breasts is relatively thin. Stretch marks often appear on the outer sides or underneath.
- Hips and thighs: Where many women gain weight during pregnancy. The skin on the hips and inner thighs is particularly susceptible.
- Lower back and buttocks: Often overlooked but common, particularly in women who gain weight rapidly.
- Upper arms: Less common but possible, especially if overall weight gain is significant.
Understanding that stretch marks are a structural change in the dermis — not a surface-level issue — is important because it explains why topical products have limited impact. Creams and oils sit on the epidermis (the outer layer) and at best penetrate slightly into it. The damage that creates stretch marks happens deeper, in the dermis, where topical products generally cannot reach in meaningful concentrations.
Who gets them and why — the genetics factor
Studies estimate that 50–90% of pregnant women develop stretch marks to some degree, with the wide range reflecting differences in study populations, definitions, and how thoroughly participants were examined. The British Journal of Dermatology has published several studies examining risk factors, and the findings consistently point to genetics as the primary determinant.
The strongest predictors of pregnancy stretch marks:
- Family history: If your mother had significant stretch marks during pregnancy, your risk is substantially higher. Skin elasticity is largely genetically determined — the amount and structure of collagen and elastin in your dermis is encoded in your DNA. No cream overrides your genetic blueprint.
- Age: Younger skin, counterintuitively, is more prone to stretch marks. Women under 20 have higher rates than women over 30. This may be because younger skin, while more elastic, has less developed collagen cross-linking and tears more readily under stress.
- Skin colour: Women with lighter skin appear more prone to visible stretch marks, though this may partly reflect the fact that stretch marks are more easily visible on lighter skin rather than occurring more frequently.
- Previous stretch marks: If you developed stretch marks during puberty (on breasts, hips, or thighs during growth spurts), you're more likely to develop them during pregnancy. Your skin has already demonstrated its tendency to respond to stretching with striae.
- Rate of weight gain: Rapid weight gain stretches skin faster, giving the dermis less time to adapt. This is one of the few modifiable risk factors.
- Baby size and multiple pregnancy: Larger babies and twin/multiple pregnancies stretch the abdominal skin more, increasing stretch mark risk.
- Polyhydramnios: Excess amniotic fluid (a medical condition) can cause dramatic abdominal expansion and severe stretch marks.
The uncomfortable truth: if your genetics predispose you to stretch marks, you will very likely develop them during pregnancy regardless of what products you use. And if your genetics protect you, you may sail through pregnancy without a single mark despite doing nothing at all. I know women in both categories, and the difference had nothing to do with their skincare routines.
What the science says about prevention
This is the section where I lose friends in the beauty industry, but the evidence is what it is. The Journal of the European Academy of Dermatology and Venereology has published systematic reviews of stretch mark prevention studies, and the conclusions are consistently disappointing for anyone selling prevention products.
The summary: No topical product has been conclusively proven to prevent stretch marks in high-quality, controlled clinical trials. Some products may help. Many do nothing. And the studies that do show benefit tend to be small, poorly controlled, or funded by the companies making the products — which doesn't invalidate them entirely but does warrant scepticism.
What the evidence actually shows:
- Cocoa butter: One of the most popular pregnancy moisturisers. A randomised controlled trial published in BJOG found no difference in stretch mark development between women who used cocoa butter and those who used a placebo. It's an excellent moisturiser — it will keep your skin soft and comfortable — but the evidence that it prevents stretch marks is weak.
- Bio-Oil: Widely used and heavily marketed. The clinical evidence for stretch mark prevention is limited. It may improve skin hydration and comfort, but no large, independent trial has demonstrated a significant reduction in stretch mark incidence.
- Centella asiatica (Gotu kola) creams: This is where the evidence gets slightly more interesting. Several studies suggest that creams containing Centella asiatica extract — which stimulates collagen synthesis — may reduce stretch mark severity. The results are not dramatic, but they're among the most positive in the literature. Products like Trofolastin (available in Europe) contain this ingredient.
- Hyaluronic acid: One study showed some benefit when hyaluronic acid was applied from early pregnancy. The proposed mechanism — that hyaluronic acid helps maintain skin hydration at a deeper level — is plausible, but replication studies are needed.
- Almond oil massage: A Turkish study found that regular massage with bitter almond oil reduced stretch mark development — but the control group received no massage at all, so it's unclear whether the benefit came from the oil or the massage (which increases blood flow to the skin). The massage component may be more important than the specific oil used.
Oils and creams: which ones have evidence?
Given the limited evidence for prevention, the question becomes: what's worth using, and what's a waste of money? My approach, after falling down the research rabbit hole, is pragmatic rather than dogmatic.
Worth trying (some evidence, no harm):
- Creams containing Centella asiatica: The best-supported ingredient in the literature. Look for products that list Centella asiatica, asiaticoside, or madecassoside in the ingredients. Apply from the first trimester.
- Hyaluronic acid moisturisers: Good evidence for skin hydration, limited but promising evidence for stretch mark reduction. Many standard facial moisturisers contain hyaluronic acid — you can use these on your body too.
- Any rich moisturiser applied with massage: If the massage is doing part of the work, the specific product matters less than the technique. Choose something that feels pleasant, absorbs well, and encourages you to actually do it daily. Consistency matters more than ingredients.
Fine for comfort, but unlikely to prevent stretch marks:
- Cocoa butter: Lovely moisturiser, smells wonderful, keeps skin comfortable. The evidence for stretch mark prevention is negative, but it certainly won't hurt and addressing itchiness (which accompanies stretching skin) is valuable in itself.
- Bio-Oil: Similar story to cocoa butter. A good product for skin comfort and hydration, but the stretch mark prevention claims outrun the evidence.
- Coconut oil: Very popular, very affordable. No clinical evidence for stretch mark prevention, but it's a perfectly fine moisturiser and unlikely to cause any problems.
- Vitamin E oil: Often recommended, but clinical trials have not shown significant benefit for stretch mark prevention specifically.
Not worth the premium:
- Any product costing £30+ that claims to "eliminate" stretch marks: If a product makes absolute claims about preventing or eliminating stretch marks, the marketing has overtaken the science. Be especially wary of celebrity-endorsed pregnancy skincare lines with luxury pricing. The ingredients are usually the same as mid-range products — you're paying for the branding.
Weight gain management and skin elasticity
The rate of weight gain is one of the few modifiable risk factors for stretch marks. Slow, steady weight gain gives your skin time to adapt — to produce additional collagen and elastin in response to gradual stretching. Rapid weight gain overwhelms this adaptive capacity, resulting in dermal tears.
NICE guidelines recommend the following total weight gain ranges during pregnancy (based on pre-pregnancy BMI):
- BMI under 18.5: 12.5–18 kg
- BMI 18.5–24.9: 11.5–16 kg
- BMI 25–29.9: 7–11.5 kg
- BMI 30+: 5–9 kg
These are ranges, not targets — every pregnancy is different, and your midwife can advise what's appropriate for you. The key point for stretch mark risk isn't the total amount of weight gained but the pattern. Gaining 14 kg gradually over 40 weeks is very different, from a skin perspective, than gaining 10 kg in the first 20 weeks and then 4 kg in the second half.
The most rapid skin stretching typically occurs between weeks 28 and 36, when the baby is growing fastest and the bump expands significantly. This is when most pregnancy stretch marks appear. Keeping weight gain steady through this period — rather than suddenly accelerating — gives your skin the best chance of adapting.
To be clear: this is not about dieting during pregnancy. Restrictive eating during pregnancy is harmful to both you and your baby. It's about eating well, responding to genuine hunger, and not confusing "eating for two" with literally doubling your intake (your caloric needs increase by only about 200 calories per day in the third trimester — roughly a banana and a yoghurt).
Nutrition for skin health during pregnancy
While no food will guarantee stretch mark prevention, certain nutrients support collagen production and skin elasticity from the inside — which is, logically, more likely to help than anything applied to the outside.
- Vitamin C: Essential for collagen synthesis. Without adequate vitamin C, your body cannot produce collagen effectively. Citrus fruits, berries, bell peppers, broccoli, and kiwi are excellent sources. A standard prenatal vitamin typically includes vitamin C, but whole food sources provide additional benefits.
- Zinc: Involved in cell division and tissue repair. Good sources include meat, shellfish, legumes, nuts, and seeds. Zinc deficiency is associated with poor wound healing and skin integrity.
- Protein: Collagen is a protein, and your body needs adequate protein intake to produce it. During pregnancy, protein needs increase — aim for roughly 60–70 grams per day from varied sources.
- Vitamin E: An antioxidant that protects skin cell membranes from oxidative damage. Nuts, seeds, spinach, and avocado are rich sources. Note: vitamin E supplements in high doses during pregnancy are not recommended — get it from food.
- Omega-3 fatty acids: Support skin barrier function and reduce inflammation. Oily fish (salmon, sardines, mackerel) is the best source — and as discussed in our seafood during pregnancy guide, two portions of oily fish per week is recommended.
- Water: Hydrated skin is more elastic than dehydrated skin. This is basic but important — keeping up your fluid intake supports skin function from the inside in a way that no amount of external moisturising can replicate.
A diet rich in these nutrients supports skin health generally, which may — emphasis on may — help your skin cope better with the stretching demands of pregnancy. It's not a guarantee, but it costs nothing extra if you're already eating well, and the same nutrients benefit your baby's development.
After pregnancy: fading, treatment, and reality
Here's the good news that nobody emphasises enough: stretch marks fade significantly over time. The angry red or purple marks of late pregnancy and the early postpartum period gradually lighten over six to twelve months, eventually becoming pale, silvery lines that are far less noticeable than their initial appearance suggests. Many women who were distressed by their stretch marks immediately postpartum find that a year later, they've become subtle enough to barely notice.
Natural fading timeline:
- 0–3 months postpartum: Marks are still red/purple, may still be slightly raised. This is their most visible stage.
- 3–6 months: Colour begins to shift from red toward pink, then toward the surrounding skin tone. Texture flattens.
- 6–12 months: Significant fading in most women. Marks become paler and flatter.
- 12+ months: Mature striae — pale, flat, sometimes slightly silvery. In many women, they're only visible up close or in certain lighting.
Post-pregnancy treatments (if desired):
- Retinoid creams (after pregnancy/breastfeeding): Tretinoin and retinol can improve the appearance of recent (red) stretch marks by stimulating collagen remodelling. They're most effective on newer marks. Prescription-strength tretinoin has the strongest evidence.
- Laser therapy: Pulsed dye laser can reduce redness in newer stretch marks. Fractional laser (such as Fraxel) can improve texture and pigmentation in mature marks. Multiple sessions are typically needed, and results vary. Costs range from £150–500 per session.
- Microneedling: Creates controlled micro-injuries in the skin, stimulating collagen production. Some studies show moderate improvement in stretch mark appearance after multiple sessions. Can be combined with topical treatments for enhanced effect.
- Chemical peels: Glycolic acid peels can improve skin texture and stimulate collagen. Effects on stretch marks are modest but may complement other treatments.
A reality check: no treatment eliminates stretch marks completely. The best outcomes reduce their visibility by 50–70%, which is meaningful but not the "complete erasure" that some clinics advertise. If complete removal is what you're hoping for, manage your expectations — improvement, not elimination, is the realistic goal.
The perspective nobody asked for (but might need)
I debated whether to include this section, because unsolicited body-positivity advice can feel patronising when you're the one staring at new marks on your skin. But here's what I've learned, eight months after my daughter was born, about the stretch marks I was so anxious about during pregnancy.
They faded. Significantly. The ones on my hips that caused that initial bathroom-mirror dismay are now pale silver lines that I have to look for to find. The ones on my lower abdomen are visible but subtle — tracks on a map of something my body did. They look like what they are: evidence that my skin accommodated a whole new person, which is — when you think about it objectively — a rather remarkable thing to do.
I won't tell you to love your stretch marks, because that feels like an instruction and emotions don't work on command. But I will say this: the gap between how significant they feel during pregnancy and how significant they feel a year later is enormous. They shrink — literally and metaphorically. The thing that consumed your attention during pregnancy becomes background by the time your baby is walking. Not because you've learned to accept it through some noble process of self-work, but because you're too busy, too tired, and too enchanted by a small person to care about lines on your skin.
Take the practical steps. Use the creams if they make you feel better. Eat well, stay hydrated, moisturise with massage. But don't let the fear of stretch marks add unnecessary anxiety to a period that has quite enough anxiety already. Whatever your skin does, it's doing it for a reason, and that reason is magnificent — even if it doesn't always feel that way at 3 a.m. in front of the bathroom mirror.
Frequently asked questions
When do pregnancy stretch marks usually appear?
Most commonly between weeks 25 and 35, when the baby is growing most rapidly and the skin is stretching the fastest. Some women notice them earlier (from around week 20), while others don't develop them until the final weeks or even just before delivery. Breast stretch marks may appear earlier than abdominal ones, as breast growth often begins in the first trimester.
Do stretch marks itch during pregnancy?
Yes — itching is very common as skin stretches. Moisturising regularly helps relieve the itch. However, if itching is severe and widespread (particularly on the palms of your hands and soles of your feet), report it to your midwife, as it can be a sign of obstetric cholestasis — a liver condition that requires monitoring. Stretch mark itching is localised to the stretching area; cholestasis itching is typically generalised and often worse at night.
Can I use retinol on stretch marks while breastfeeding?
Retinoids (retinol, tretinoin) are not recommended during breastfeeding as a precaution, although the evidence of risk from topical application is limited. Most dermatologists advise waiting until after you've finished breastfeeding to use retinoid products. In the meantime, hyaluronic acid, vitamin C serums, and alpha-hydroxy acids (like glycolic acid) are considered safe and can help improve skin texture.
Will my stretch marks get worse with a second pregnancy?
Existing stretch marks from a first pregnancy may become more visible during a second pregnancy as the skin stretches again. However, you may not develop many new ones — the skin has already stretched and adapted, and some women report fewer new marks in subsequent pregnancies. This is highly individual and, again, largely genetic.
Does Bio-Oil work for pregnancy stretch marks?
Bio-Oil is an effective moisturiser that can help with skin comfort and hydration during pregnancy. However, clinical evidence for its ability to prevent stretch marks is limited. It may help reduce the severity of marks or improve how the skin feels, but it cannot override genetic predisposition. If you enjoy using it and it keeps your skin comfortable, continue — just manage your expectations about prevention.
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