Pregnant people may develop new moles or other marks on their skin. Most are harmless. It is possible to develop melanoma during pregnancy, however, so have a doctor check any marks that are causing concern.

Moles form when clusters of cells, called melanocytes, overproduce melanin, the pigment that colors the skin.

The National Library of Medicine notes that people can develop new moles at any age and that hormonal changes during pregnancy can cause new moles to form.

This article explores the link between pregnancy and moles. It also looks at other common skin changes during pregnancy and why it is important to contact a healthcare professional about any difference in the appearance of a mole.

A pregnant person with moles.Share on Pinterest
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Moles can form at any time. They usually appear during childhood and puberty, and sometimes during pregnancy, due to hormonal changes.

Can moles disappear during pregnancy?

Moles can fade or completely disappear throughout a person’s lifetime.

The European Academy of Dermatology and Venereology reports that pregnancy does not significantly alter the way moles look. But changes in their appearance can occur.

Existing moles may become more noticeable, particularly those on the chest or abdomen. As the skin expands to accommodate the growing fetus, moles may spread out and become larger and darker. More than 10% of pregnant people may find that this happens.

Moles on the back and limbs are unlikely to change in size due to pregnancy.

Melanoma is a type of skin cancer. As the American Academy of Dermatology (AAD) states that pregnancy does not increase the risk of developing melanoma.

However, as it notes, melanoma typically develops during child-bearing years.

If a doctor diagnoses melanoma during pregnancy or within 12 months of delivery, healthcare professionals refer to this as “pregnancy-associated melanoma”. This can affect 10–26 in 100,000 pregnancies.

How does melanoma affect pregnancy?

The AAD says that it is safe to test for melanoma during pregnancy. A doctor takes a biopsy using a local anesthetic, which is safe during pregnancy.

The outlook for both the pregnant person and the fetus is better with early detection and treatment.

If melanoma has spread, doctors may need further tests, and they should explain the risks and likely benefits. Some tests may not be possible during pregnancy.

Treatment options for early stage melanoma are safe during pregnancy. The doctor uses a local anesthetic and removes the melanoma.

In the later stages, the treatment options are limited. A doctor may recommend using interferon, a type of immunotherapy.

The best approach to treatment may depend on the location of melanoma. People who are pregnant and have melanoma on their face or neck may have radiation therapy. But radiation therapy may harm the fetus if a person receives it for melanoma around their abdomen.

Melanoma is a type of cancer that can cross the placenta. However, it is very rare, the AAD notes, for a baby to be born with it, even when the person giving birth has advanced melanoma.

The body changes in many ways during pregnancy. A person may develop acne or stretch marks.

As The American College of Obstetricians and Gynecologists reports, other skin changes during pregnancy include:

The Centers for Disease Control and Prevention (CDC) recommend seeing a doctor about any sore that does not heal or any new or old growth that changes shape or size.

For people concerned about melanoma, the CDC recommends following the “ABCDE plan,” which involves contacting a doctor in any of these circumstances:

  • Asymmetry: A mole has an unusual shape, and the two halves look different.
  • Border: The mole has an uneven, possibly a jagged, edge.
  • Color: Different parts of the mole are different colors.
  • Diameter: The mole is bigger than a pea.
  • Evolving: The mole changes over weeks or months.

Most moles are harmless patches of highly pigmented skin. They can appear at any time, particularly during periods of increased hormonal activity, such as pregnancy.

People who are pregnant may also notice that moles on the chest or abdomen become larger or darker during pregnancy.

As always, it is important to check for signs of skin cancer, including melanoma. Being pregnant does not increase the risk of melanoma, but it can develop during pregnancy. In the early stages, the treatment is safe for the person and their fetus.

Anyone concerned about a mark on their skin should contact a doctor.