What Is Lanugo?

Newborn baby being given a bath

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What Is Lanugo?

Lanugo is a special type of body hair found on newborn babies. The sight of a baby covered in hair can be distressing, but it is perfectly normal. Not all babies are born with lanugo, but all of them were coated with it in the womb. The hair usually goes away before birth, but sometimes it sticks around until a baby is born or even for a few months after.

Most often, this soft, downy hair appears on preemies, but full-term newborns are sometimes born with lanugo, too. While it can be a surprise for parents to see, it's not a cause for concern. Learn more about why this baby hair is there, how long before it typically goes away, and when, in rare instances, it could be a sign of a problem. 

Why It's Important

Lanugo is part of an important developmental stage for your baby. The term lanugo comes from the Latin word "lana" which means wool. This body hair appears to have many functions and researchers are continuing to study it and learn more about what it does.

Lanugo is the first hair that grows out of your baby’s hair follicles while they are still developing in the womb.

What we know is that babies lose their lanugo while they are still in the womb, or shortly thereafter. It falls off into the amniotic fluid. Babies drink that fluid—along with whatever else is floating in it. After the baby takes in the lanugo, it will make its way through their system and become part of their first poop (meconium). 

It's thought that the important functions of lanugo include the following:

Skin Protection

In the womb, a thick, white, greasy substance called vernix caseosa coats your baby's skin, providing a barrier to protect them from the amniotic fluid that surrounds them in the womb. Lanugo sticks to the vernix to help it stay in place on the skin. If the vernix did not have the hair to cling to, it could slide off the baby's body.

As your baby gets closer to their due date (40 weeks), they will have less lanugo, less vernix, and less protection against the effects of floating in amniotic fluid. You can often see these effects when a baby is overdue, as they tend to have wrinkly, peeling skin.

Temperature Regulation

Your baby does not start to put on significant weight or develop a layer of fat to keep them warm until the last few months of pregnancy. The growth of lanugo is believed to play a role in helping them regulate temperature, hold in heat, and keep warm inside the womb.  

Hormonal Regulation

Another theory is that the movement of lanugo on your baby’s skin might play a role in the release of hormones that reduce stress and stimulate their growth inside the womb.

What to Look For

Lanugo may look like white or dark hair, or it may not have any pigment or color at all. You might be able to see and feel lanugo on your baby’s back, shoulders, arms, forehead, and cheeks. The hair may be sparse and minimal or more widespread. It can occur in just a few spots or coat most of the body.

The hair can be found anywhere on the body except for the parts that do not have hair follicles—such as the lips, palms of the hands, soles of the feet, sides of the fingers and toes, genitals, and nails. 

Variety of Appearance

Lanugo will show up differently in different babies. Depending on the length of your pregnancy it can be absent or abundant. Your family’s genetics will also play a role, making the hair lighter or darker. Here are a few ways lanugo might appear.

  • Genetic factors: Lanugo might be light or have no color in babies with lighter skin. Babies with darker complexions tend to have darker hair and, therefore, darker lanugo. The dark color of the hair may make it more noticeable. 
  • Overdue (post-term): Babies born after 42 weeks do not usually have any visible lanugo. 
  • Preemies: Babies tend to shed their lanugo the closer they get to being full-term. If a baby is born early (before 37 weeks), they will often have a lot of lanugo and it might take longer to go away.
  • Term infants: A term newborn (37 to 42 weeks) may or may not have visible lanugo. Lanugo is present in up to 30% of full-term newborns. 

Duration

Lanugo begins to show up on your baby's skin around the fourth or fifth month of your pregnancy (by about 16 to 20 weeks gestation). At approximately 28 weeks, the lanugo is at its most abundant. After this point, a baby's layer of lanugo usually starts to shed. Beginning after the seventh or eighth month of pregnancy, there will typically be progressively less and less of the hair until it all disappears.

If your child is born with lanugo, it will most likely fall out and go away on its own within a few weeks. However, it's normal for it to last longer, especially if your baby is a preemie.

Many full-term babies lose all their lanugo before they are born, but some do not. Whether your baby’s lanugo falls out before or after they're born, it will eventually go away. When it does, another type of hair will grow in its place. The new hair is called vellus hair.

Vellus hair is similar to lanugo but thinner and not as noticeable. This hair will cover your baby’s body throughout childhood. Lanugo and vellus hair are not the same as the hair on the head or the hair that develops during puberty (terminal hair).

Tips

You don't have to do anything special to treat the lanugo on your premature baby or newborn, but the following tips will help you care for your baby's body hair.

  • Be patient. Time is the best treatment for newborn lanugo. Leave your baby’s hair alone and it will eventually disappear. In a few days or weeks, your newborn should lose lanugo—but if it lasts longer, that can still be normal.
  • Don’t use hair removers. Do not wax, shave, or use a body hair remover to get rid of your baby's lanugo. These products are not safe for infants and could harm their delicate skin.
  • Try gentle massage. Massaging the area of skin very gently with mild baby oil might help expedite lanugo falling out, but use extreme care to prevent damaging your baby’s skin. Only use products that will not irritate your baby’s skin or eyes.  
  • Talk to the doctor. Your doctor or your baby's pediatrician can answer your questions and reassure you that, more likely than not, the hair is nothing to worry about and will go away on its own.

When to Worry

It's common to see lanugo on newborns, but once it goes away in the weeks or months after birth, it should not grow back. The development of lanugo after the newborn period or later in life can be a sign of several medical conditions, including the following:

Extreme Malnourishment

Lanugo can indicate poor nutrition—usually to the point of starvation. This state might be caused by eating disorders such as anorexia or other conditions that cause severe weight loss. Lanugo develops when someone does not have enough body fat to keep them warm. A layer of soft, downy hair grows to protect and insulate the body. Once a person's nutritional status improves, lanugo should go away.

Genetic Disorder

Hypertrichosis Lanuginosa is a rare genetic disorder that causes excessive growth of lanugo or lanugo-like hair. An infant can be born with the condition or it can develop later in life. The rare disorder is sometimes called "wolfman" or "werewolf syndrome." When it develops later in life, the disorder is sometimes triggered by a health condition, eating disorder, or the side effect of a medication. 

Other Health Problems

Studies have shown that, although rare, lanugo can be a sign of certain health conditions, including cancer, endocrine disorders, or metabolic disorders.

A Word From Verywell

Lanugo is a natural part of fetal development, and it's perfectly normal if your baby is born with this soft body hair. Don't worry, it typically disappears after the newborn stage, but if your baby’s lanugo lingers beyond a few months, ask your pediatrician. If lanugo develops on an older child, teenager, or adult, talk to your doctor. It could indicate a serious health problem that needs treatment. 

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Article Sources
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Additional Reading
  • U.S. National Library of Medicine. Premature infant. Reviewed October 11, 2018.