Moles (melanocytic naevi) during pregnancy

Moles (also known as melanocytic naevi) are normal and a common type of skin growth. They develop when melanocytes, cells that produce colour (pigment) grow in clusters on your skin.

Most people have moles. Usually, you are not born with moles. They develop on your skin during childhood and adolescence. By the age of 15 years, Australian children have an average of 50 or more moles.

Most moles are brown. They can vary in colour from pink to black. Moles are usually flat, relatively even in colour and regular in shape. Some moles are raised, and these moles are usually light in colour and soft to touch.

When you are pregnant, there is a chance your moles may change, especially in your first trimester. They can grow larger and become darker. This is especially seen in your moles on your abdomen (tummy) and breasts, as your skin stretches.

While your moles may get bigger when you are pregnant, they are not more likely to become malignant (dangerous) during pregnancy.

Your moles should go back to how they were before within 12 months of giving birth.

While you are pregnant, it is important to check your moles. Make sure that they are not developing any features that may be worrying. See your doctor if you're not sure.

Some moles can become itchy. This is a sign to look out for.

The genes that you inherited from your parents influence if you will develop moles.

Sunlight is another important cause of moles. Exposure to sunlight during your childhood and teenage years makes you more likely to develop moles.

During pregnancy, your stretching skin and hormonal changes can make your moles appear darker or larger.

You should see your doctor if you notice that your mole:

• is asymmetrical (not round)
• has an irregular border
• has different colours or shades within it
• is larger than 6mm in size
• is raised
• has changed in the size, shape or colour during your pregnancy

If you know you have moles that are slightly irregular, you must have scheduled skin checks. Your doctor will discuss with you how often you must have your check-ups.

If you see your midwife, they may refer you to a doctor to examine your skin.

Your doctor will assess your moles using the ABCDE method. They will look for:

• Asymmetry
• Border irregularity
• Colour variation
• Diameter (size) of more than 6 mm
• Elevation or Evolution (change in size, shape or colour)

If your doctor is worried about any of your moles, they will take a biopsy (a sample of the mole). It will be sent to the lab to check if the mole is cancerous or not.

If your mole is cancerous, your doctor will refer you to specialist doctors. This will give you and your baby the best possible outcome.

Usually, moles do not need treatment.

You may have your mole removed if:

• your doctor is worried it may be cancerous
• your mole bothers you and you want it removed for cosmetic reasons

There is a very small risk your mole developing into melanoma, a type of skin cancer.

In the unlikely event that one of your moles become cancerous during your pregnancy, and you develop melanoma, it is very rare for the melanoma cells to cross the placenta and affect your baby.

Moles cannot be entirely prevented since the number of moles you have is mainly influenced by your genetics.

Self-care tips to help prevent moles

Protecting your skin from the sun starting from a young age can reduce the number of moles you develop. This is because sunlight exposure, especially during childhood and adolescence, contributes to the development of moles.

Visit Cancer Council to learn how to check for signs of skin cancer with the ABCDE melanoma detection guide.

Learn to be SunSmart, as early detection of skin cancer saves lives.

Download the SunSmart telephone app, to check the UV index before you head outdoors.

Read about self-care for expecting and new parents at PANDA.

Other languages

Visit the Healthy Horizons website in a range of community languages to learn about general health conditions. These include several skin diseases, reproductive health and mental health.

Aboriginal and/or Torres Strait Islander peoples

You can find out more about Aboriginal and/or Torres Strait Islander pregnancy health on Stronger Bubba Born or watch the How to Have a Safer Pregnancy video.

Looking for information for sexually and gender-diverse families?

PANDA provides inclusive and appropriate support for LGBTIQA+ expecting and new parents.