The Fascinating Truth Behind Newborn Body Hair (Lanugo)

Is heartburn kicking your pregnant butt? Think you might be expecting a little hairball? You might have heard of the old wives’ tale that heartburn equals a hairy baby.

When we think of hair, our immediate thought is the usual strands we have on our head. But there’s another type that’s generally only seen on newborn babies — officially known as lanugo.

Today we’ll talk about just that — what it is and why it develops, and whether it can grow back later.

What Is Lanugo?

Lanugo is fine unpigmented hair that begins to grow on the baby from the fourth or fifth month of pregnancy (source).

It’s the first hair that grows from the follicles. It grows everywhere on your baby, except for the palms, lips, and soles of the feet.

Premature babies tend to have more lanugo when they’re born. Although some full-term babies still have some left by the time they’re born, most actually shed this hair inside the womb before the eighth month.

The lanugo begins to grow on the scalp, where it spreads down the face, around the eyebrows, nose, and forehead. It then continues down the baby’s body, until it reaches the feet.

When it begins to shed inside the uterus, the hair incorporates into the amniotic fluid.

You know that first dark green squirt of poop our lovely newborn greets us with, called meconium? Yeah, we have lanugo to thank for that. When it dissolves in the amniotic fluid, this is swallowed by the baby, who later disperses of it in their diaper.

When the lanugo sheds, two types of hair replace it: vellus (fine hair) and terminal (thick hair). Terminal hair is what we have on our scalp, arms, and legs.

What’s the Purpose of Lanugo?


Lanugo serves a great purpose inside the uterus. It helps the cheese-like substance, called vernix, to adhere to the baby’s skin by acting as a physical anchor. Without lanugo, the vernix wouldn’t have a chance of sticking to the smooth skin.

This, in turn, helps the vernix fulfill its purpose of keeping the baby’s skin protected from the amniotic fluid.

Another amazing fact is that the lanugo actually helps to increase the baby’s growth rate around mid-gestation. But then toward the end, it decreases the rate of growth (source).

The lanugo hairs send vibrations through the vernix every time your baby moves. When these reach the amniotic fluid, they activate sensory receptors that connect to the nerve endings. These will ultimately end up stimulating your baby’s growth.

Once it gets closer to the last month, the lanugo hair sheds. The stimulation will stop, and the growth rate slows down.

How Long Does Lanugo Remain After Birth?

Only about 30 percent of babies still have lanugo when they’re born. This is no big deal. You may not even notice it straight away, since it hides under the vernix.

If lanugo is still present, don’t worry. Your newborn won’t look like a baby chimp forever. The hair generally fall outs during the first few weeks. Although, some babies may keep it for as long as a few months!

There is conflicting advice regarding the removal of lanugo if it persists.

Some moms recommend that you apply a little olive oil to your baby’s skin and then give a gentle massage. Do this twice a day, and the hairs should loosen their grip.

You can also make a little paste from gram flour, turmeric powder, and milk, and then massage it in. But do this before a bath, since turmeric can temporarily stain the skin.

Nonetheless, the general advice is to allow the hair to fall naturally. A baby’s skin is sensitive and massage could cause irritation, however gentle the products used may be. If you’re concerned that it’s taking too long, contact your pediatrician for advice.

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Can Lanugo Regrow Later in Life?

Lanugo hair can occasionally regrow in older children or adults. However, this is a bigger mystery and might be a sign of a more serious health issue.

When lanugo regrows on adults, it’s often confused with the thin vellus hair. However, one way to check this is by examining the overall health of the person, as well as the location of the hair. If it grows in new places, for example the face or hands, it’s likely to be lanugo.

There are some conditions that can contribute to lanugo regrowth, including:

1. Eating Disorders

In extreme cases, eating disorders, like anorexia and bulimia, can lead to malnutrition. Studies suggest that, under these circumstances, the body seems to enter a survival mode, where it tries to preserve body heat. This triggers the lanugo hairs to regrow to compensate for the missing insulation (source).

It’s more prevalent among younger adults and adolescents. The hairs generally regrow around the forearms, back, and upper body.

2. Cancer

Some types of cancer and tumors can contribute to the development of lanugo in adults. However, this is rare.

A study from 2007 mentions a person with prostate cancer who developed fine, lanugo-like hair. The study reported that the hair disappeared after treatment and did not reappear (source).

In another study in 1978, it was also reported that a man with lung cancer began to grow lanugo-like hair. This hair grew on his face, hands, feet, and torso (source).

However, lanugo hair is not a telltale sign of cancer, and these studies remain inconclusive. There are few reports of the association of lanugo and cancer.

3. Does It Require Treatment?

Lanugo hair is a biological occurrence that only exists to keep the body safe. For adults, there’s no need for treatment since it should disappear on its own, once the body feels it’s no longer needed.

A Patch of Hair Near the Spine

Some mothers may notice that their newborn has a patch of hair near the spine, on the lower back. This is not lanugo hair and is caused by something completely different.

1. Spina Bifida

Spina bifida is a congenital disability that affects the spine. It occurs when the baby’s backbone doesn’t develop properly. This may lead to a damaged spinal cord and nearby nerves, causing different disabilities.

The name spina bifida means “open” or “split” spine, since sometimes this condition can cause an opening in the back.

In severe cases, the spine will be visible from the outside, and the child will need surgery to correct it. However, in milder cases, there is no opening, and the defect is hidden (source).

This condition takes place during the first month of pregnancy as the baby’s spine and the nearby nerves develop.

The severity of this condition varies greatly. Mild versions of this defect may only cause minor problems, if any at all. However, severe cases can lead to weakness, loss of bladder control, or even paralysis.

2. Spina Bifida Occulta

Children born with a mild version, called spina bifida occulta, may sometimes have it without even knowing. In Latin, “occulta” means hidden, and it basically means that the defect sits under the skin.

There’s almost no way of telling if a baby has this type, unless some symptoms are apparent. However, this type does leave one clue on the lower part of the spine. Sometimes it’s a birthmark or a dimple, or a patch of hair.

When looking from the inside, the spinal cord is likely attached to the tissue as opposed to being afloat in the spinal column. This may or may not cause any issues for the baby. Fortunately, most babies with this condition won’t experience any long-term problems.

3. Causes of Spina Bifida

Spina bifida generally occurs when your body doesn’t have enough folic acid during the first month of pregnancy. Folic acid is vital for tissue formation, cell growth, and development.

Low levels of this vitamin, both before pregnancy and in the early weeks, will increase the risk of spina bifida, and other neural tube defects.

Sometimes it still occurs, even though the mother has a sufficient amount of the vitamin, although this is rare. In these cases, doctors suspect it could be a genetic defect.

If the mother ran a high fever during her pregnancy, or took the drug valproic acid for epilepsy, there’s also an increased risk.

Does a Hairy Baby Cause Heartburn?

Well, we can’t talk about hairy babies without asking this question, can we? So you’ve probably heard the old wives’ tale, but is it true?

For a long time doctors didn’t think twice before they said “no.” However, recent research actually proved them wrong! Hairy babies do apparently cause heartburn.

You see, the high levels of estrogen during pregnancy relax the sphincter at the end of the esophagus. This enables stomach acids to glide up and irritate, leading to heartburn.

Studies have revealed that the same hormones which cause heartburn, also stimulate hair growth in the baby (source).

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The Hairy End

So there you have it. Although giving birth to a little hairball may make you second guess your genes, lanugo is perfectly normal. It’ will shed soon enough, so rest assured there’s nothing to be concerned about.

However, watch out for a small patch of hair on the lower back. If you spot one, mention this to your pediatrician, as there is a small chance it could be spina bifida occulta.

Was your baby born with lanugo? We’d love to hear your experiences. How long did it last? Feel free to share your comments below — and please share our page, too!

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