In short. Stretch marks appear where a body region changes size or shape faster than the dermis can rebuild itself. Pregnancy, adolescent growth, weight change, rapid muscle gain, steroid medicines and inherited connective tissue conditions are the recognised settings, and the tendency to tear runs in families.
Key points
- Pregnancy is the commonest setting, with marks usually appearing in the third trimester.
- Growth spurts, weight change and rapid muscle gain all outpace the dermis.
- Steroids weaken the dermis directly, so marks can appear with no stretch at all.
- Connective tissue conditions are a rare cause, considered when other features appear.
- A family history raises the likelihood of tearing but does not settle it.
Pregnancy is the commonest setting
The abdomen, breasts and hips change size over months, and the dermis is asked to keep up. Marks usually appear in the third trimester, though breast marks can arrive earlier because that change is fast. A second pregnancy starts from a dermis that already holds scar tissue.
Growth spurts, weight change and training
The teenage growth spurt is the other classic setting, and it is why marks are common in adolescents who are otherwise well: height gained quickly pulls on the dermis of the back, the thighs and the knees. Rapid muscle gain produces them in men, most often across the shoulders, chest, upper arms and lower back.
Every one of these settings changes the size or shape of a body region faster than the dermis can rebuild itself. That is the whole of the mechanical story, and it means the advice that follows is about pace rather than about skin care, which is not what most people expect to hear.
Steroid medicines weaken the dermis directly
Steroids weaken the dermis directly, so marks can appear with no stretch at all. Taken by mouth, given by injection, or applied to the skin in a strong preparation over a long period, they produce broad bands across the abdomen, flanks, breasts and armpits. This is the one setting here that is a medical matter.
When do connective tissue conditions matter?
Inherited conditions affecting connective tissue make the dermis more fragile, so marks appear earlier, more widely and after less stretch than usual. They are a rare cause, considered when marks arrive with unusual joint flexibility, a tall lean build, easy bruising, or a family history of problems with the heart valves or the aorta. Rare is not the same as impossible, and these features are asked about rather than assumed absent.
Why stretch marks run in families
How much collagen and elastin a dermis holds, how extensible the weave is and how well it repairs are inherited. Two people can share a pregnancy, a weight change or a training programme and end up with different skin. A mother or a sister with the same marks is useful information rather than a coincidence.
Which settings need a doctor, not a cosmetic plan?
Marks appearing during steroid treatment, by mouth, by injection or on the skin need medical assessment. So do marks with weight gain around the middle, easy bruising or muscle weakness, and marks with unusual joint flexibility or a family history of aortic problems. These settings need a doctor rather than a cosmetic plan.
| Setting | What changes | Where marks appear | What it means |
|---|---|---|---|
| Pregnancy | The abdomen, breasts and hips change size over months | Usually in the third trimester; breast marks can arrive earlier | A later pregnancy starts from scar tissue |
| Teenage growth spurt | Height is gained quickly | Back, thighs and knees | Common in adolescents who are otherwise well |
| Rapid muscle gain | Muscle size increases quickly | Shoulders, chest, upper arms and lower back | Most often seen in men |
| Steroid medicines | The dermis is weakened directly, with no stretch needed | Broad bands across the abdomen, flanks, breasts and armpits | This is the one setting here that is a medical matter |
| Connective tissue conditions | The dermis is more fragile | Earlier, more widely and after less stretch | A rare cause, considered when other features appear |
| Family history | Collagen, elastin, weave and repair are inherited | The same tendency seen in relatives | Raises the likelihood rather than settling it |
Sources
- American Academy of Dermatology: patient information on stretch marks and who is affected
- National Institute for Health and Care Excellence: guidance on skin conditions in primary care
- Cochrane Library: systematic reviews on stretch mark prevention and treatment
Internal links
Frequently asked questions
Are stretch marks more common in a first pregnancy or a later one?
Later pregnancies usually produce more of them, and the reason is cumulative rather than hormonal. Each pregnancy stretches a dermis that already contains scar tissue from the previous one, and scar tissue has less reserve than the original fabric. A first pregnancy in skin with plenty of reserve may leave nothing behind, while the same person may develop marks in a second.
Do stretch marks appear more on the breasts or on the abdomen?
Both are common, and they tend to appear where the change in size is fastest rather than where it is largest. Breasts often change early in a pregnancy and quickly, which is why marks there can arrive before the abdomen has grown much. Hips and thighs change with weight, and the shoulders and upper arms with training.
If my mother has stretch marks, will I definitely get them?
Not definitely, and it is still useful information. The tendency to tear runs in families because the structure and repair capacity of the dermis are inherited, so a family history raises the likelihood rather than settling it. Bringing that history to an assessment helps, because it changes how much weight the skin is expected to carry.
Risks & Limitations
- No treatment removes a stretch mark. Improvement in colour and texture is the realistic aim.
- A mark that has already gone pale answers to far less than one that is still red.
- Change is judged from standardised photographs over months, not from the first weeks.
- Laser and light can leave pigment change, particularly in skin that darkens readily after injury.
When to Seek Care
- Marks that appeared while you were taking a steroid medicine, by mouth or on the skin.
- Marks with weight gain around the middle, easy bruising or muscle weakness.
- Marks with unusual joint flexibility, or a family history of aortic or heart valve problems.
- Blistering, spreading redness or increasing pain after a treatment on the skin.
References & Further Reading
- American Society of Plastic Surgeons (ASPS) — procedure and safety guidance
- National Institute for Health and Care Excellence (NICE, UK) — relevant guidance
- Cochrane Library — systematic reviews
- Chinese Medical Association Plastic Surgery Branch — clinical guidance
This page is patient education, not medical advice, and it does not cite individual studies. Discuss your own case with a qualified clinician. To arrange an assessment at Chongqing West District Hospital, see Contact & Consultation.