When Does Baby Hair Texture Change?

Published on July 9th, 2020

baby-hair-texture

There are so many things about your baby that you cherish. Like, how easily she fits in your arms, that sweet baby smell, even the delight she takes in dropping food on the ground.

Just like the tininess of his toes and his penchant for Peekaboo, your child’s hair today may not be your child’s hair for life. Your child is growing and developing every day, from his tiny toes to his hair follicles. These changes your baby goes through often sparks questions like “how will my baby look,” and that is completely normal! 

According to neonatal experts, by the age of two your child’s locks are locked in. But until then, hair grows and changes. That’s why the answer to “When will my baby’s hair texture change?” isn’t as simple as you might think.

How Does Baby Hair Texture Work? 

To understand your baby’s changing hair, let’s start with some key hair terms:

  • Hair Shaft – You’re probably already familiar with the hair shaft—right now, you might have thousands of them tied up in a ponytail or clipped to the side with a bobby pin. The hair shaft is the part of your hair that isn’t anchored below the surface layers of skin in the hair follicle. 
  • Hair Follicle – A hair follicle is a bit like a tunnel in the epidermis—the surface layers of the skin—and goes all the way down into the dermis—the thicker layer of the skin that resides below the epidermis. This is where hair is “grown.”
  • Hair Root – The hair root, or the bulbous base of the hair shaft, anchors your hair to the follicle

For every individual hair strand, the hair growth cycle occurs in three stages: 

  • Anagen Phase – In the anagen phase, cells quickly divide at the hair’s root at the base of the follicle. This cell growth pushes the hair out of the follicle and out over your baby’s scalp. This phase lasts between two and seven years. 
  • Catagen Phase – The catagen phase marks the end of the hair’s active growth. For two or three weeks, the hair is cut off from the protein-supplying capillaries in the base of the follicle, preventing the strand from growing.
  • Telogen Phase – During the final stage of the hair growth cycle, the hair follicle rests. For two to four months, no new hair growth occurs, and instead, you may shed some of your hair. In fact, about 25 to 100 telogen hairs are shed normally each day. At the end of the telogen phase, the cycle begins right back at the anagen phase. Thankfully, these phases apply to individual hair strands, and not every follicle is on the same schedule. Otherwise, every two to seven years we’d all be bald! 

Pregnancy Fun Fact: During pregnancy, the increase in hormones tends to prevent this final telogen phase, resulting in thicker hair. When the hormone levels return to normal (typically around 3-4 months post-delivery), this can result in excessive hair loss. This phenomenon is called telogen effluvium.

This three-part cycle doesn’t begin at birth. In fact, this cycle of hair growth only applies to terminal hair, which is the hair we have as adults. Terminal hair typically grows in by the age of two, and two stages of hair development occur before the terminal stage.

When Does Baby Hair Texture Change: The Phases of Baby Hair

During his first 24 months, your baby’s hair texture will dramatically change as it goes through three phases:

Baby Hair Phase 1: Lanugo

While in utero, your baby’s hair follicles produce a soft, thick hair called lanugo. This unpigmented hair begins to appear at five months of gestation and grows all over your child’s body as well as her head. Scientists are still developing theories as to the biological function behind lanugo, but a 2009 study suggests that this hair might play a role in fetal hormone development. 

Usually lanugo hair is lost during the later stages of gestation and absorbed into the amniotic fluid. However, sometimes your child will be born with her lanugo—this is perfectly natural. Typically, at birth, your child’s lanugo hair is in the telogen phase, meaning it’s primed for shedding within the next few weeks. 

Baby Hair Phase 2: Vellus Hair 

Lanugo hair is replaced with the finer, nearly transparent body hair known as vellus hair. If you want an immediate visual for these hairs, just take a look at the fine hairs on your arm, the back of your hands, and even your torso. These vellus hairs can be found all over your baby’s body, even on the top of your baby’s head. According to Advanced Neonatal Care, vellus hairs can make up between 6-25% of your baby’s scalp hair. The rest will either be lanugo or terminal hair, depending on the stage of your baby’s hair growth.

Baby Hair Phase 3: Terminal Hair 

Throughout these phases, your baby’s hair follicles are growing and developing into his unique shape and form. By about two years of age, your child’s vellus scalp hair will be replaced with thicker, longer, and darker hair. These hairs are your child’s terminal hairs—adult hair. These hairs will then cycle through the anagen-catagen-telogen phases mentioned above.

Puberty Fun Fact: As your child progresses through puberty, vellus hair will develop on the face, armpits, chest, abdomen, legs, arms, pubic area, and feet. This is colloquially called “peach fuzz.” For boys (much more so than for girls), this vellus hair will transition to terminal hair. 

How Does Baby Hair Texture Change? 

The texture of your child’s lanugo hair may be drastically different than his terminal hair. That’s because, over time, the diameter of your child’s follicles enlarge as your child grows. And as the diameter changes, the shape of the follicle develops into its adult form. 

The best way to picture this? Break out some pasta dough.

A pasta maker presses dough through holes to create different noodle shapes. For example, the hole shapes of a rotini maker will result in tight curling pasta, while a spaghetti maker will create thin, straight pasta. The shape of the pasta boils down to the shape of the hole the dough passes through. 

Before your stomach starts to growl from this metaphor, turn your mind back to your child’s hair. Think of her follicles like a pasta-shaper. As the hair shaft (or “dough”) grows, the follicle shapes it into its unique texture, resulting in curls, waves, or straight strands. 

Stanford University’s genetic department gives a general overview to follicle shape and the resulting hair strand: 

  • Round Follicles – If your baby’s follicles are perfectly round, she’ll have straight hair. 
  • Oval Follicles – The ovular shape of a follicle will cause the hair strand to grow in a “spiral” effect, resulting in curly hair.
  • Somewhere in the Middle – A not-quite-oval and not-quite-circle follicle will result in a hair strand that grows halfway between curly and straight, creating wavy hair or kinky hair.

But what determines the shape of your child’s follicle? Or the thickness of each strand of hair? 

Hair type is determined by genetics.

The Genetics of Hair Texture 

Just like the color of your child’s eyes or the dimples in his cheeks, the texture of your baby’s hair depends on genetics. Follicle shape can be determined by a variety of different genes based on your child’s ancestry. Here are just a few genes that come into play, according to the US National Library of Medicine’s genetics center:

  • EDAR The EDAR gene is one of many genes that’s linked to thick, straight hair, especially within East Asian populations.
  • FGFR2 – Along with the EDAR gene, the FGR2 gene is associated with hair texture and thickness.
  • TCHH – Some scientists have theorized that the TCHH gene is related to differences in hair textures, particularly in people with northern European ancestry. This gene is also responsible for giving the body instruction on making trichohyalin, a protein found in hair follicles that links keratin molecules together to help make the hair shaft.

Dominant vs Recessive: An Oversimplification on Genes

When you think of genetics, you might think of Punnett Squares, a model of determining gene possibilities through dominant and recessive alleles. However, human genetics don’t quite fit into that tidy dominant-recessive box. In fact, Punnett Squares have proven to be an oversimplification of how many genes work.

Much like hair color, hair texture is polygenic—that means the texture of your baby’s hair is determined by the way multiple genes interact, not just one gene. 

How to Find Out Your Baby’s Hair Texture

As you wash your baby’s fine lanugo hair, or soothingly stroke her vellum hair with your fingers, you might be wondering what your baby’s true hair will finally look like. But, besides the wait-and-see method, there’s only one dependable way to discover your baby’s hair texture—through a simple DNA test.

Coming in the fall of 2020, the SneakPeek Early Traits DNA Test can help you learn more about your child’s development—and you don’t have to be a geneticist to conduct the test. Simply rub your child’s inner cheek with a cotton swab. Then, send off the cotton swab in a prepaid envelope to let the genetic experts do their work. In less than three weeks, you’ll find out your baby’s hair texture and thickness—along with a few more amazing insights. 

Answers to questions like “How tall will my child be?”, “What color hair will my baby have?”, or even “Will my baby’s eyes stay blue?” are right at your fingertips. You can learn your baby’s eventual height, hair color, and even the pattern of his irises. You can also discover key information about your child’s development, like her unique nutritional profile and sleep patterns. With SneakPeek Early Traits DNA Test, you can learn more about the incredible ways your baby will grow.

SneakPeek Early Traits DNA Test 

From their hair to their toes to their amazing brains, babies have a lifetime of growing to do. As a parent, you naturally want to know every little detail about your baby’s growth—it’s how you can give your child the best love and care possible. So, give yourself (and your child) the gift of knowledge with SneakPeek Early Traits DNA Test this fall.

 

Sources: 

  1. University of Utah. DEBUNKING OLD WIVES’ TALES: BABY’S HAIR. https://healthcare.utah.edu/the-scope/shows.php?shows=0_3tcvsb6o
  2. What To Expect. Newborn Haircare. https://www.whattoexpect.com/first-year/ask-heidi/newborn-hair.aspx
  3. University of Wisconsin-Madison. Hair from infants gives clues about their life in the womb. https://news.wisc.edu/hair-from-infants-gives-clues-about-their-life-in-the-womb/
  4. Stanford University. Understanding Genetics. https://genetics.thetech.org/ask-a-geneticist/hair-texture-can-change
  5. US National Library of Medical Science. Is hair texture determined by genetics? https://ghr.nlm.nih.gov/primer/traits/hairtexture
  6. The Washington Post. Dear Science, Why Does The Hair On My Head Grow Longer Than The Hair on My Body? https://www.washingtonpost.com/news/speaking-of-science/wp/2016/07/19/dear-science-why-does-the-hair-on-my-head-grow-longer-than-the-hair-on-my-body/?arc404=true
  7. US National Library of Medicine. Hair follicle dermal papilla cells at a glance. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3115771/
  8. Open Text. Layers of the Skin. https://opentextbc.ca/anatomyandphysiology/chapter/5-1-layers-of-the-skin/
  9. Science Direct. Novel mechanism of human fetal growth regulation: A potential role of lanugo, vernix caseosa and a second tactile system of unmyelinated low-threshold C-afferents. https://www.sciencedirect.com/science/article/abs/pii/S0306987708004957
  10. Healthline. What it Means if Your Baby is Losing Hair. https://www.healthline.com/health/baby/baby-hair-loss#causes
  11. Medical News Today. What is Vellus Hair? https://www.medicalnewstoday.com/articles/319881
  12. US National Library of Medical Science. Role of Hair Papilla Cells on Induction and Regeneration Process of Hair Follicles. https://pubmed.ncbi.nlm.nih.gov/9893172/
  13. Wiley University Online Library. The Biology and Genetics of Curly Hair. https://onlinelibrary.wiley.com/doi/full/10.1111/exd.13347
  14. Khan Academy. Variations on Mendel’s Law. https://www.khanacademy.org/science/biology/classical-genetics/variations-on-mendelian-genetics/a/variations-on-mendels-laws-overview
  15. UniProt. UniProtKB – Q07283 (TRHY_HUMAN)Basket. https://www.uniprot.org/uniprot/Q07283
  16. American Pregnancy. Hair Loss During Pregnancy. https://americanpregnancy.org/pregnancy-health/hair-loss-during-pregnancy/
  17. Today’s Parent. Pregnancy Hair Changes. https://www.todaysparent.com/pregnancy/pregnancy-hair-changes/#:~:text=That’s%20because%20during%20pregnancy%20you,be%20attributed%20to%20hormonal%20fluctuations.
  18. Healthline. 6 Natural Remedies to Pregnancy Acne. https://www.healthline.com/health/pregnancy/acne-remedies#:~:text=Many%20women%20experience%20acne%20during,bacteria%2C%20inflammation%2C%20and%20breakouts.
  19. Healthline. Why Hair Loss Can Occur During or After Pregnancy and What You Can Do. https://www.healthline.com/health/hair-loss-in-pregnancy

SneakPeek aims to provide the most accurate and up-to-date information to help our readers make informed decisions regarding their health before, during, and after pregnancy. This article was written based upon trusted scientific research studies and/or articles. Credible information sources for this article are cited and hyperlinked.

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