What is lanugo?

The expert answers:
Lanugo is the name given to the soft, fine, downy hair that covers a newborn. It is more frequently seen in premature infants as it begins to be shed in-utero during the final month of pregnancy.

Some post-term infants are born with minimal lanugo. The amount of lanugo is variable and some parents are concerned by the amount of hair covering their new infant. The hair can cover all skin except for the lips, palms of the hands and soles of the feet, sides of the fingers and toes, nails, glans of the penis and insides of the labia minora and majora.

This hair will invariably be shed by three to four months after birth. It is replaced by hair covering the same surfaces called vellus hair, but this hair is finer and more difficult to see. The more visible hair that continues into adulthood is called terminal hair. This forms in specific areas and is hormone dependant.

Lanugo, even in the most extreme cases, will be shed and should not be treated. Some cultures have remedies to hasten the shedding, but this is unnecessary.