Birthmark, medically known as mother spot or mole, is an abnormal proliferation of skin tissue during development, which appears on the skin surface with abnormal shape and color.

Birthmarks can be found at birth or slowly appear a few months after birth. Some birthmarks may last a lifetime, while others may fade over time.

Birthmarks are usually divided into two types: vascular birthmarks and pigmented birthmarks.

1. Vascular birthmark is caused by abnormal development of blood vessels or lymphatic vessels under the skin. Depending on the depth of blood vessels or lymphatic vessels under the skin, the color of this birthmark can range from pink, red to cyan.

2. Pigmented birthmarks are usually brown, gray, emerald blue or black, which is caused by abnormal development of pigment cells. Some birthmarks are also called moles.