Friday, January 27, 2012

Baby Hair Growth

        Thanks to my wonderful friend and (almost) Doctor K., I was able to get hold of the article that discusses infant hair growth.  I was interested in this topic because nearly everyone I see comes and tells me what a "beautiful baby boy" I have. Even when she is dressed in pink. Well, everyone, Q-ball is a girl. Apparently, her short hair leads people to assume she is a boy. Yet, when I correct these very friendly well-wishers, they are quick to tell me that their daughter also had short hair "until she was almost two!"  (Leading me to wonder why they are quick to assume that a short-haired baby is a boy..) So, I wondered, what is normal for infant hair growth?
    Here's what I learned...
Development of hair in the human fetus.
  • Hair actually starts forming very early in the life of a fetus- at 8 weeks the hair bud is developing and by 10 weeks hair follicles are formed in a very, very precise pattern.  All of your hair follicles are perfectly, evenly spaced!
  • No new hair follicles are formed after birth.  
  • The number of hair follicles a person has largely depends on race.  African-Americans have 100,000-150,000 hair follicles; Asian-Americans have 90,000-120,000; and Caucasians have 100,000-150,000.
  • At 15 weeks, the hairs start to protrude through the skin, always at a slight angle. 
  • Throughout the rest of gestation, the fetus hair goes through two cycles of shedding all hair and then regrowing.  These cycles are typically slower in infants with darker complexions, resulting in more hair at birth.
  • Eight to twelve weeks after birth, hair goes through its final phase, often resulting in nearly complete hair loss.
  • At birth and up to about 8 weeks after, isolated areas of baldness are normal.  
  • Hair typically grows from the forehead to the nape of the neck.
  • At birth, infants have vellus hair which is very thin and silky and very lightly colored.  Between 3 to 7 months, intermediate hair develops.  Finally, by 2 years, terminal hair develops which is like grown-up hair.
  • Hair color is the result of melanin, the same pigments that cause the color of skin.  These pigments travel down to the hair bulb and become part of the hair shaft, helping form the hair color.  
  • Only two pigments are responsible for all hair color: Eumelanin forms brown to black hair, and pheomelanin forms yellow-blond to red hair.
  • Infant hair growth varies a lot between infants.  But, for each infant, the hair length for the entire head should be pretty consistent .
  • Most babies develop hair whorls- a clockwise spiral of hair growth.  56% of hair whorls are located left of the middle of the head, likely because the left side of the brain is slightly larger.
  • I liked this quote from a medical journal, "In the newborn periods, unruly hair that sticks out straight despite attempts at grooming is normal."
     So, based on this information, I assume that Q-ball will develop her beautiful, girly locks around age 2- which is exactly what Q-ball's well-wishers state!  Experienced parents could have written this article, no doubt! 

Did your newborn lose all of his hair? When did you baby's hair finally start growing?

Furdon, S. & Clark, D. (2003) Scalp hair characteristics in the newborn infant.  Advances in neonatal care. 3(6), 286-296.

    1 comment:

    1. I'm so glad you got your hands on the article. This is very interesting! Annabelle had a full head of hair at birth, but it was not particularly thick and was very short. I never noticed any hair loss, just a gradual filling in and lengthening. Now, at just shy of 23 months, she has long curls in the back, and shorter ones elsewhere. It's funny to try for a ponytail, because it can only include about a third of her hair - everything around the outside is too short!


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