Skin Changes in Pregnancy: Melasma, Linea Nigra and Stretch Marks

What is actually happening

Most pregnancy skin changes come down to two mechanisms: more melanin, and more stretch.

ACOG lists the common changes together: dark spots on the breasts, nipples or inner thighs; melasma; linea nigra; stretch marks; acne; spider veins; varicose veins; and changes in nail and hair growth. On the pigmentation ones it is specific — "dark spots and patches are caused by an increase in the body's melanin, a natural substance that gives color to the skin and hair". On the rest it is refreshingly honest: "Some are due to changes in hormone levels that happen during pregnancy. But for most skin changes health care professionals are not sure of the exact cause."

The NHS describes the same darkening in plainer terms: hormonal changes "may make your nipples and the area around them go darker", and "your skin colour may also darken a little, either in patches or all over".

Melasma — the mask of pregnancy

The NHS describes "darkened skin on your face or brown patches" and names it: chloasma, or the mask of pregnancy. ACOG describes melasma as brown patches "on the face around the cheeks, nose, and forehead".

What to expect: ACOG says dark spots and melasma "usually fade on their own after you give birth", but adds the honest qualifier that "some women may have dark patches that last for years", and that a dermatologist can discuss treatment if it does not settle.

The one thing that genuinely changes the course is sun protection. ACOG: "To help prevent melasma from getting worse, wear sunscreen and a wide-brimmed hat every day when you are outside. The sun's UV rays can reach you even on cloudy days." That is a prevention-of-worsening measure, not a cure — but it is the only lever on this page that clearly does something.

Linea nigra

ACOG defines it as "a dark line that runs from the navel to the pubic hair", and groups it with the other pigmentation changes caused by increased melanin. Many people notice a faint line was already there — pregnancy simply darkens it. It fades along with the other dark patches after birth, though it can take months.

Stretch marks

The NHS says stretch marks affect "around 8 out of 10 pregnant women". Cochrane's reviewers put striae gravidarum at 50% to 90% of women. Either way, they are the norm rather than the exception.

They form "when the middle layer of skin (dermis) becomes stretched and broken in places", usually on the tummy, thighs or breasts. The NHS notes they "can be pink, red, purple or brown, depending on your skin colour" — which is useful, because most photographs online show one skin tone. The first sign is often itchiness where the skin is thinning.

Whether you get them is largely not up to you: the NHS says it "depends on your skin type, as some people's skin is more elastic", and notes a higher chance with above-average weight gain. For context it puts typical pregnancy weight gain at about 10 to 12.5 kg (22 to 28 lb), while stressing this varies a lot and that dieting in pregnancy is not the answer.

Afterwards, the NHS is straight with you: "the marks may gradually fade into paler scars and become less noticeable. They probably will not go away completely."

Do the creams work?

This is the clearest evidence on the page, and it is negative. The Cochrane review of topical preparations for preventing stretch marks in pregnancy pooled six trials involving 800 women and found no statistically significant difference between active creams and placebo or no treatment (average risk ratio 0.74, 95% CI 0.53 to 1.03), nor any difference in severity, nor any difference between one active preparation and another. Its conclusion: "We found no high-quality evidence to support the use of any of the topical preparations in the prevention of stretch marks during pregnancy."

The NHS says the same about products sold to remove existing marks — "there is no reliable evidence that they work" — and that evidence on preventing them with oils or creams is limited. ACOG is blunter: "There is no proof that any of these treatments work. Using a heavy moisturizer may help keep your skin soft, but it will not help get rid of stretch marks."

Moisturise because it feels good and helps the itch. Do not spend money expecting prevention.

Acne, and what not to use

ACOG notes acne is common in pregnancy, including in people who have never had it. The treatment question matters more than the acne does, because several standard treatments are off the table.

ACOG lists over-the-counter ingredients that can be used in pregnancy: topical benzoyl peroxide, azelaic acid, topical salicylic acid and glycolic acid. And it lists what should not be used: oral isotretinoin, which "may cause severe birth defects"; topical retinoids, which are generally recommended to be avoided; oral tetracyclines, which can discolour a baby's teeth and affect bone growth; and hormonal acne therapies. If an ingredient is not on the safe list, ACOG's advice is to check with your obstetrician or midwife before using it.

What is not just a skin change

One symptom on this page is a genuine red flag, and it is easy to dismiss as dry pregnancy skin.

Itching without a rash. The NHS says to get urgent medical help if you have very itchy skin — "for example, it keeps you awake at night" — if the palms of your hands or soles of your feet are itchy, or if the itching is worse at night. These can be signs of intrahepatic cholestasis of pregnancy, a liver condition that needs a blood test and treatment. Call your maternity unit, or 111 if you cannot reach them.

ACOG also lists the less common pregnancy skin conditions worth knowing by name: PUPPP (pruritic urticarial papules and plaques of pregnancy), prurigo of pregnancy, pemphigoid gestationis, and intrahepatic cholestasis of pregnancy. All are treatable; none should be self-diagnosed.

One more: ACOG advises that if "a tender, red spot appears on your leg, it should be checked by your health care professional" — that is a blood clot check, not a vein cosmetics question.

When to call someone

• Urgently, today: itching without a rash, itchy palms or soles, or itching that is worse at night or keeping you awake (NHS).
• Same day: a tender, red, hot spot on your leg (ACOG).
• Routinely: blisters, a spreading itchy rash, or any skin change you are unsure about — the uncommon pregnancy skin conditions are treatable once named.
• Before treating acne with anything not on ACOG's safe list.

The short version

Darker patches, a dark line and stretch marks are ordinary, mostly fade, and mostly cannot be prevented. Sunscreen genuinely helps melasma; creams genuinely do not prevent stretch marks. And itching without a rash is not a skin change — it is a phone call.