Birthmarks are marks on the skin that a baby can develop before birth or soon after. They can occur anywhere on the skin and are caused by overgrowth of blood vessels, melanocytes, smooth muscle, fat, fibroblasts, or keratinocytes. Dermatologists divide birthmarks into two types: pigmented birthmarks and vascular birthmarks.
Pigmented birthmarks are caused by excess skin pigment cells and include moles, café au lait spots, and Mongolian spots.
Vascular birthmarks, also called red birthmarks, are caused by increased blood vessels and include macular stains (salmon patches), hemangiomas, and port-wine stains. A little over 1 in 10 babies have a vascular birthmark present by age 1.
Most birthmarks are harmless and some go away as the child grows. Doctors dont know what causes most birthmarks, and they cant be prevented. They are not caused by anything done or not done during pregnancy, and most arent related to trauma to the skin during childbirth. Some kinds may run in families, but a genetic cause hasnt been found.
Doctors can remove moles and occasionally café-au-lait spots with surgery, though larger ones may be harder to remove. Laser treatment can remove café-au-lait spots, but these often return. A doctor should check a birthmark when it first appears to see what type it is, and to decide what monitoring or treatment it needs, if any.
Birthmarks are harmless markings on the skin and are not caused by something a birthing parent did or didn’t do during pregnancy. They’re natural additions to a persons appearance and may or may not be noticeable. If someone doesn’t like how their birthmark looks on their skin, they can talk to a healthcare provider about removing it.
