Mongolian blue spots in babies: Need-to-know information

Mongolian blue spots in babies: Need-to-know information

Read and learn about these rather common birthmarks in newborns...

Newborn babies do not always have flawless skin. Dry, peeling skin and acne are just two of the ‘problems’ these little ones may face. Birthmarks are also commonly seen on newborn skin and sometimes, may raise some concern among parents, especially if the birthmark has an unusual appearance or colour. This article is all about one type of birthmark common among newborns -Mongolian blue spots.

What are Mongolian blue spots?

Also known as slate gray nevi and formally known as dermal melanocytosis, Mongolian blue spots are a type of pigmented birthmark. True to their name, they are bluish-gray in colour, varying from a very dark blue to a lighter gray and with the colour usually uniform over the whole birthmark.

Mongolian blue spots are can vary in size, but most are a few centimetres across and don’t have clearly demarcated edges. They are flat, not raised.

Typically, these birthmarks are present on the buttocks and/or lower back, but are occasionally found on a baby’s arms or legs.

They are usually present at birth, or develop soon after.


The spots commonly appear on a baby’s lower back and/or buttocks. Image: Pinterest

What causes them?

When the baby is still in the womb, the cells that will eventually form the skin move to the surface. According to medical experts:

“A particular type of cell called a dermal melanocyte moves to the top layer of the skin between the 11th and 14th week of pregnancy.

“These dermal cells usually disappear by the 20th week of pregnancy. Doctors believe that Mongolian blue spots are the result of these cells not moving to the top layer of skin and not disappearing.”

And because these cells are trapped deep within the skin, the area takes on a blue-grey hue.

How common are Mongolian blue spots?

These birthmarks are very common in children of Asian, Middle Eastern, African and Mediterranean background, with as many as three-quarters of children from these groups born with them, say medical professionals. However, Mongolian blue spots are rare in children of European background.

They can occur in both genders but are slightly more common in boys, although the reasons for this occurrence are not known.

Mythology around Mongolian blue spots

According to a Korean myth, Mongolian blue spots occur when a shaman spirit of childbirth — Samshin halmi — slaps the baby’s bottom so that he or she exits mummy’s womb!

In China meanwhile, these blue spots are known as ‘mark’ (taiji). The story here is that when a baby is born, he or she gets a ‘spank’ from God as a start to life.

And Japanese mythology has it that a Mongolian blue spot (known in Japanese as ‘asshirigaaoi’ or ‘blue bottom), is believed to be the result of mummy and daddy having sex during pregnancy!

Should you be worried about your baby’s Mongolian blue spots?

While seeing these birthmarks on a newborn might be quite alarming for parents especially since they resemble bruises, rest assured that they are non-cancerous, not painful and present no health danger to your child.

Occasionally, the spots may be mistaken for the symptoms of a spinal condition known as spina bifida occulta. But, according to the Spina Bifida Association, these spots are reddish in colour and not the distinctive blue-grey colour of Mongolian blue spots.

Almost always, the spots fade away by the time your child is around five and generally disappear during the teenage years. Should they linger into your child’s adolescent years and he or she is disturbed by them, speak to a doctor about possible options.

Sometimes, Mongolian spots may be associated with extremely rare (seen in fewer than one in every 100,000 newborns) metabolic problems such as mucopolysaccharidosis or gangliosidosis.

If your child appears to have Mongolian blue spots at birth, do get a doctor to confirm that they are indeed blue spots. Also, if you notice that the spots change colour or appearance, you should consult a doctor without delay.

Why parents should take pictures of these spots at birth

As mentioned earlier, Mongolian blue spots may look like bruises or ‘spank marks’ and might be mistaken for them by concerned teachers or daycare providers, if the birthmarks are still present when your child is older.

For this reason, it is advised to take pictures of these spots while your baby is a newborn and keep them with you. When he is older and if you are starting him with a new daycare provider and he still has his Mongolian blue spots, it’s important to mention the presence of these birthmarks.

If necessary, show the pictures too, to avoid any misunderstandings.


Indian Journal of Dermatology, Venereology and Leprology

MedlinePlus (Ann Pietrangelo and Kristeen Cherney)

*Featured image from Stanford Medicine (Janelle Aby).

This article is republished with permission from theAsianparent. 

We hope you have found this article informative and useful. Do look out for other theAsianparent Sri Lanka articles related to newborn care and commonly occurring conditions, too. 

Any views or opinions expressed in this article are personal and belong solely to the author; and do not represent those of theAsianparent or its clients.
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