Fetal Development: Your Baby's Hair | BabyCenter

Will your baby have a head like a fuzzy peach? A fluffy mane that sticks straight up? Swirls of curls? Whatever your baby's hair looks like at birth, it's likely to change in the first year of life.

In fact, your baby's hair journey begins in the second trimester, when a fine hair called lanugo develops.

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Key Takeaways

• Lanugo is the soft hair that forms on your baby's body around week 21.
• Lanugo helps protect your baby from the harmful effects living in fluid can have on tissue and regulates their body temperature.
• It's likely your baby's lanugo will fall out by week 36, but up to 30% of babies are born with some lanugo still on their bodies.

What is lanugo and what does it look like?

Lanugo is a soft hair that develops on your baby's body around week 21 of pregnancy. The follicles actually start forming deep in your baby's skin at 14 weeks, but the hair doesn't fully emerge until weeks later. Described as being fine and downy, the hair is unpigmented, meaning there's no color.

It typically first sprouts on the forehead, eyebrows, and upper lip before appearing further down the body. Eventually, it covers the whole body. Most babies lose their lanugo before birth, but some babies will still have some at birth and for a few weeks after.

Why do babies have lanugo?

Lanugo serves an important purpose: It helps to hold the vernix caseosa, a thick white substance that surrounds your baby, in place.

Also known simply as vernix, this covering protects your baby's skin from damaging fluids in the amniotic sac, helps regulate your baby's temperature, prevents water loss, and contributes to the baby's innate immunity. Lanugo makes that all possible!

When will your baby's hair grow in the womb?

Lanugo first emerges at 21 weeks, but it begins developing several weeks before. Here's a quick guide:

Weeks pregnant	Milestone
14 weeks	Hair follicles have begun to form.
21 weeks	First hairs sprout on forehead, eyebrows, and upper lip.
22 weeks	Hair is visible on the head, and fine, downy lanugo covers the body – especially the shoulders, back, ears, and forehead.
23 weeks to birth	Melanin starts being produced, adding color to hair.
33 to 36 weeks	Lanugo is shed.
26 to 40 weeks	Vellus hair (peach fuzz) replaces lanugo.
Birth	Some lanugo may still be present – it will fall out in weeks.

Lanugo is only the first type of hair your baby will grow. Once the lanugo falls out, it's replaced by vellus hair. This is the soft hair that coats our bodies, commonly called "peach fuzz."

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Finally, your baby will develop terminal hair, the relatively thick hair on their head that will eventually spread to their underarms and genitals during puberty.

Interestingly, the hair follicles on your baby's scalp form a pattern that will remain for life. And new follicles don't form after birth, so babies are born with all the hair follicles they'll ever have.

What color will your baby's hair be?

Predicting your baby's hair color isn't easy. Experts think that many different genes control the precise amount of melanin that's made inside each strand of hair, but they don't know for certain how these genes interact to produce the huge range of possible hair colors.

So be prepared for surprises, as your child's hair color – and texture – can come from any corner of the family tree.

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Also, how your baby's hair looks at birth isn't necessarily how it'll look later. Babies often gradually lose their hair within the first 6 months of life and grow new hair in its place (this is more common among white infants than babies of color). What grows back in may look similar or be a different color or texture entirely.

Signs your baby will have a lot of hair

Genetics are the strongest indicator of how much hair your baby will have. If you and your partner have thick hair, it's likely your baby will, too.

When will your newborn's lanugo fall off?

Lanugo typically falls out around 33 to 36 weeks. This means it may fall out in the womb, or, if your baby comes early, it may still be on their body for a few weeks after birth.

My babies were hairy but lost most of it because it was their lanugo hair from the womb. - BabyCenter Community member Carlybabylove

Is it normal for babies to be very hairy when they're born?

Yes, up to 30% of babies will still have lanugo on their bodies at birth. This is especially true if they're born premature, because the layer on lanugo may not have been shed yet.

"My babies were hairy but lost most of it because it was their lanugo hair from the womb," says BabyCenter Community member Carlybabylove.

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