Mongolian spots are a slight blue tinge on the back or bottom after a baby has been lying down. Slightly darker patches on the back or buttocks can sometimes be seen throughout the first three months.
In theory this is more common in African American and Asian babies but is seen in many Caucasian babies as well. Watch this video to learn more.
![](https://i.ytimg.com/vi/fjR7xSp9mwo/mqdefault.jpg)