Lanugo is fine, downy hair; it is a type of pelage.

In humans

Fetal development

Lanugo grows on fetuses as a normal part of gestation, but is usually shed and replaced by vellus hair at about 40 weeks of gestational age. As the lanugo is shed from the skin, it is normal for the developing fetus to consume the hair with the fluid, since it drinks from the amniotic fluid and urinates it back into its environment. Subsequently, the lanugo contributes to the newborn baby's meconium. The presence of lanugo in newborns is a sign of premature birth.

Malnutrition

Lanugo is also a common symptom of serious anorexia nervosa, as the body attempts to insulate itself when body fat is lost. Lanugo may also occur in individuals who are malnourished due to lack of access to adequate food.

In non-human animals

Lanugo is also common on other animals. For example, seals and elephants are often born with a covering of lanugo.

References

External links

• Photo of lanugo in a human infant, The Royal Infirmary of Edinburgh