Pregnancy stretch marks most commonly appear during the sixth and seventh months, as the belly and breasts expand rapidly in the late second and early third trimesters. Up to 90% of pregnant women develop them, though they can show up earlier or later depending on how quickly your body is growing and several personal risk factors.
The Typical Timeline
Most women first notice stretch marks around weeks 24 to 28, when the rate of abdominal growth accelerates. The skin on your belly, breasts, and thighs is stretching faster than the underlying connective tissue can keep up with, and small tears form in the deeper layer of skin called the dermis. These tears show up on the surface as indented, slightly raised streaks.
Some women see marks as early as the end of the first trimester, particularly on the breasts, which begin changing size well before the belly does. Others don’t develop any visible marks until the final weeks before delivery, when the baby’s size peaks. A smaller number of women never develop them at all.
What They Look Like at First
New stretch marks are reddish, purplish, or pinkish streaks that may feel slightly raised or swollen to the touch. This early stage reflects active inflammation in the torn dermal fibers. Some women report itching or a feeling of skin tightness in the days before marks become visible, though not everyone notices these sensations.
Over time, the color fades. After delivery, the marks gradually transition from those reddish streaks into pale, slightly depressed scars with a wrinkled texture. This shift from the red phase to the white, silvery phase can take months to a couple of years. The structural change underneath is permanent: the normal elastic fibers in the skin get replaced by short, disorganized fibers that never fully return to their original form.
Where They Appear
During pregnancy, the three most common locations are the abdomen, breasts, and thighs. The abdomen takes the most noticeable hit because it undergoes the greatest amount of stretching, but marks also frequently develop on the hips, buttocks, lower back, and upper arms. Essentially, any area where the skin is pulled rapidly over a short period is vulnerable.
Why Some Women Get Them Earlier or Worse
Several factors influence both the timing and severity of stretch marks, and most of them are outside your control.
- Age: Younger women are significantly more likely to develop stretch marks. In one study, women who developed marks averaged about 26.5 years old, while those who didn’t averaged 30.5. Younger skin may seem more resilient, but it actually contains more hormone receptors that make the connective tissue more reactive to the changes of pregnancy.
- Weight gain: Women who gained more weight during pregnancy had a much higher rate of stretch marks. Those who developed marks gained an average of 15.6 kg (about 34 pounds), compared to 12.5 kg (about 28 pounds) in women who didn’t. Faster, greater weight gain means faster stretching, which increases the chance of dermal tearing.
- Family history: Genetics play a clear role in severity. Having a mother or sister who developed significant stretch marks during pregnancy didn’t dramatically raise the overall chance of getting them, but it was strongly linked to developing moderate or severe marks. About 45% of women with a family history had moderate to severe marks, compared to only 22% of those without.
- Baby size: Higher birth weight and longer gestational age at delivery were both associated with more severe marks, likely because a bigger baby means more abdominal stretching in those final weeks.
What’s Happening Under the Skin
Stretch marks aren’t just a surface issue. They form when the connective fibers in the dermis, the thick middle layer of your skin, tear under mechanical stress. During pregnancy, rising levels of cortisol (a stress hormone that increases steadily throughout pregnancy) reduce the skin’s elasticity by affecting how collagen and elastic fibers behave. At the same time, estrogen and progesterone are climbing, and the skin has been shown to contain elevated levels of receptors for these hormones in areas where marks form.
The result is a kind of double hit: the skin is being stretched more than usual while the hormonal environment makes its structural fibers less capable of withstanding that stretch. Once those fibers tear, the body fills in the gaps with scar-like tissue rather than rebuilding the original elastic network. That’s why stretch marks change in color and texture over time but don’t fully disappear on their own.
Can You Prevent or Reduce Them
No cream, oil, or lotion has been proven to prevent stretch marks entirely. Products containing cocoa butter, vitamin E, or almond oil are widely marketed for this purpose, but clinical evidence supporting them is weak. Keeping skin well-moisturized may reduce itching and discomfort, but it won’t stop the deeper dermal tearing that causes the marks.
The most practical step you can take is managing your rate of weight gain. Since rapid weight gain is one of the strongest modifiable risk factors, gaining weight steadily and within recommended ranges gives your skin more time to adapt. This won’t guarantee prevention, especially if your genetics and age put you at higher risk, but it reduces the mechanical stress on your skin during the peak stretching period in the third trimester.
For marks that have already formed, treatments are more effective during the early red phase than after they’ve faded to white. Options like topical retinoids (not safe during pregnancy, only postpartum), laser treatments, and microneedling have shown varying degrees of improvement in the appearance of marks, particularly when started early. None of these erase stretch marks completely, but they can make them less noticeable over time.