lanugo n : the fine downy hair covering a human fetus; normally shed during the ninth month of gestation
EtymologyLatin, from lana ‘wool’.
Lanugo is hair that grows on the body in an attempt to insulate the skin because of lack of fat. It is a type of pelage. Lanugo is very fine, and may grow densely on the body in places where significant amounts of hair does not normally grow. It occurs 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.
Lanugo is also common on other animals. For example, seals and elephants are often born with a covering of lanugo.
Lanugo is also a common symptom of serious anorexia nervosa, as the body attempts to insulate itself when body fat is lost.
lanugo in Spanish: Lanugo
lanugo in French: Lanugo
lanugo in Dutch: Lanugo
lanugo in Polish: Lanugo