Stretch marks in pregnancy usually first appear in the second trimester, most often between weeks 13 and 21, as the belly begins to grow faster than the skin can comfortably keep up with. They are narrow, streak-like lines on the skin — called striae gravidarum in medical language — that start out pink, red, or purple and usually fade to a paler, silvery colour after birth. They are not dangerous, they do not mean anything is wrong with the pregnancy, and they are extremely common: published estimates put them at 50% to 90% of pregnant people, with most reviews settling around 70% to 90%. If you are watching your belly change week by week, a pregnancy week-by-week guide can help you place new marks on the timeline of your own pregnancy.
What Stretch Marks in Pregnancy Are
Stretch marks in pregnancy are tears in the middle layer of the skin, the dermis, that form when skin stretches quickly and its elastic fibres cannot keep pace. The central entity here is the stretch mark itself: a line where the dermis has stretched beyond its elastic limit, while the outer layer of skin, the epidermis, stays intact. That is why a stretch mark feels like normal skin, not like a cut or a wound — the surface is unbroken, and the colour you see comes from the stretched tissue and blood vessels underneath.
Two forces create them together, and neither alone explains the full picture. The first is mechanical stretching: the abdomen expands by roughly 30 to 40 centimetres in circumference over a full-term pregnancy, and the breasts, hips, and thighs grow too. The second is hormonal: rising cortisol in pregnancy weakens elastic fibres in the skin, so the dermis is less springy than usual at exactly the moment it is being asked to stretch the most. That combination — weaker fibres plus faster stretching — is why stretch marks are a pregnancy phenomenon rather than a simple side effect of gaining weight at any other time of life.
Where Stretch Marks Usually Appear
Stretch marks in pregnancy most often appear on the abdomen, and then on the breasts, hips, thighs, and buttocks. The abdomen is first because it grows the most and the fastest, especially from the second trimester onward. Breast marks often follow breast growth in the first and second trimesters, while hip and thigh marks tend to appear later, as weight gain and fluid retention change the lower body. Some people get marks in only one area, others in several; both patterns are normal, and the location says nothing about the health of the pregnancy.
When Do Stretch Marks Appear in Pregnancy?
Stretch marks in pregnancy typically appear between weeks 13 and 21, in the second trimester, and become most noticeable in the third trimester. The second trimester runs from week 13 to week 27, and this is when the uterus rises out of the pelvis and the belly starts to show clearly — the point at which stretching speeds up. A smaller number of people notice the first faint lines earlier, around weeks 10 to 12, especially if the breasts grow quickly in the first trimester. Others see nothing until weeks 30 to 36, when the belly grows fastest of all.
The timing is not a deadline, and there is no week by which stretch marks "should" have appeared. About 10% to 30% of pregnant people never develop visible marks at all, and their absence is not a sign that the skin is healthier or that the pregnancy is different in any medical sense. Genetics plays a large part: if your mother or sisters developed stretch marks in pregnancy, your own odds are higher, because skin elasticity varies from person to person. Other factors that raise the odds include a twin or multiple pregnancy, rapid weight gain, a younger age at pregnancy, and a higher pre-pregnancy body mass index — all of which increase either the speed of stretching or the total amount of stretch.
What Stretch Marks Look Like as Pregnancy Progresses
Stretch marks in pregnancy change colour over time, and that colour change is the best clue to how old a mark is. New marks, called striae rubrae, are pink, red, reddish-brown, or purple, and they may feel slightly raised or itchy. The colour comes from blood vessels showing through the thinned, stretched skin. Over the months after birth, most marks fade into striae albae: flatter, paler, silvery-white lines that blend closer to the surrounding skin. The change is gradual — fading takes roughly 6 to 12 months after delivery for most people — and the marks rarely disappear completely.
Itching deserves a mention of its own, because it is the symptom people actually notice day to day. As the skin stretches, it also dries out, and dry, tight skin itches. Mild itching over the belly in the second and third trimesters is common and usually harmless. Itching that is severe, widespread, or concentrated on the palms and soles is different: that pattern can be a sign of intrahepatic cholestasis of pregnancy, a liver condition that needs prompt medical review. The distinction matters — ordinary stretch-mark itch stays where the skin is stretching, while cholestasis itch tends to be intense and in places where there are no marks at all.
Can Stretch Marks in Pregnancy Be Prevented?
No cream, oil, or butter has been proven to prevent stretch marks in pregnancy, and that honest answer matters more than any product claim. A Cochrane review (2012, updated in later summaries) examined topical preparations for preventing stretch marks and found insufficient evidence that any of them — cocoa butter, olive oil, almond oil, or vitamin E creams — reliably prevents marks from forming. The trials were small, the products varied, and the results were inconsistent. That does not mean moisturisers are useless: keeping skin hydrated can reduce itching and tightness, which is a real benefit even if it does not stop marks.
What does have evidence behind it is steadier, slower weight gain within the recommended range for your starting weight. Rapid gain stretches skin faster, and faster stretching is exactly what the dermis struggles with. A pregnancy weight gain calculator can show the Institute of Medicine ranges — for example, 11.5 to 16 kilograms total for someone starting at a healthy weight — so you can see whether your own gain is tracking steadily rather than in sudden jumps. Staying hydrated, eating a varied diet with enough vitamin C and zinc for collagen formation, and avoiding smoking (which damages elastic fibres) all support skin health in general, even though none of them guarantees mark-free skin. The information-gain point competitors often miss is this: because hormones weaken elastic fibres in pregnancy, even people who gain weight slowly and moisturise daily can still develop marks — prevention advice that promises otherwise is selling certainty the evidence does not support.
Do Stretch Marks Go Away After Birth?
Stretch marks in pregnancy usually fade substantially after birth but rarely vanish entirely. The fading happens for two reasons: the skin is no longer being stretched, so the dermis stops tearing, and the blood vessels that made new marks red or purple gradually constrict, so the colour softens. Most people see clear fading within 6 to 12 months of delivery, and the marks that remain are typically thin, pale, and much less noticeable than they were at their reddest. Breastfeeding does not make marks worse, and the marks themselves do not affect breastfeeding or the baby in any way.
Treatment after pregnancy is a separate question, and the evidence there is stronger — but the timing matters. Prescription retinoid creams (tretinoin) have the best evidence for improving newer, red marks, yet they are not used during pregnancy or breastfeeding because of safety concerns for the baby. Laser and microneedling treatments can improve older marks, but they are cosmetic and costly, and usually considered only after breastfeeding ends. For most people, the realistic expectation is fading, not erasure.
Stretch Marks and Other Pregnancy Skin Changes
Stretch marks in pregnancy sit alongside several other common skin changes. The linea nigra is a dark vertical line down the centre of the belly, caused by increased melanin, and it usually fades after birth. Melasma is patchy brown pigmentation on the face, again driven by hormones and sunlight. If a rash is blistered, painful, or spreading rapidly, that is not a stretch mark pattern and deserves a clinician's look, just as the palm-and-sole itching pattern does.
New marks often arrive in the same weeks as other familiar changes. The pregnancy symptoms week-by-week guide covers the common patterns, and other posts in this cluster cover when pregnancy cravings start, whether cramping is normal in early pregnancy, and what nesting in pregnancy feels like.
When to Ask a Clinician About Stretch Marks
Stretch marks in pregnancy almost never need medical treatment, but three situations are worth raising at your next appointment or sooner. First, itching that is severe, keeps you awake, or affects the palms and soles, as described above, should be checked promptly for cholestasis. Second, a mark that becomes hot, swollen, painful, or oozing may be infected or may be something else entirely, such as a skin condition unrelated to stretching. Third, distress about the marks themselves is a legitimate reason to ask: if they are affecting how you feel about your body, a clinician can talk through realistic fading timelines and, after birth, the treatment options that actually have evidence. None of these situations means something is wrong with the pregnancy — they are simply the points where a professional look beats internet reassurance.
The Bottom Line on Stretch Marks in Pregnancy
The bottom line on stretch marks in pregnancy is that they usually appear between weeks 13 and 21, affect roughly 70% to 90% of pregnant people, start red or purple, and fade to pale lines over the 6 to 12 months after birth. No cream prevents them reliably, steady weight gain within the recommended range helps more than any product, and moisturiser earns its place by easing itch rather than by stopping marks. They are a normal record of how fast your body grew to make room for a baby — not a flaw, not a failure of skincare, and not a medical problem.
If you are tracking how your body is changing, start with the basics: confirm where you are with a due date calculator, check that your weight gain is tracking steadily, and note when the first marks appear so you can watch them fade on their own schedule. And if the itching ever moves to your palms and soles or becomes severe, call your clinician the same day rather than waiting for the next routine visit.