"When I was pregnant, my hair changed from straight to curly."
"Really? Mine did the exact opposite. I always had curly hair, but during pregnancy it fell flat."
That surprised me. I'd never heard of such a thing. This weekend at a baby shower I remembered those notes, and wondered if hair really did change during pregnancy. I mean, doesn't my friend pictured here have that third trimester glow, right down to her soft, lustrous hair? When I thought about it, I'd experienced pretty good hair days during my pregnancies, too.
So I decided to browse around for info. As usual, trying to learn one thing leads to learning another. On my first hit, at Webmd, I discovered hair grows in phases.
Hair normally grows in three phases: active growth, resting, and shedding. During these phases, people typically shed 100 hairs every day.That surprised me, too. In all my hairpisodes, I don't remember coming across the three phases of hair growth. Webmd goes on to explain how hormones in the body during pregnancy alter the phases. And, the hair gets thicker. Literally.
When you're pregnant, the extra hormones coursing through your body shift your hair cycle. Your hair grows or stays on your head and doesn’t shed. This is why your hair seems longer and thicker than usual.
Some research also suggests that hair strands actually thicken during pregnancy. "The diameter of the hair increases," Mirmirani says. "We measured hair diameter in the third trimester and after pregnancy, and it's definitely thicker during pregnancy."
Sometimes, a woman's hair becomes more or less curly during or after pregnancy.
"We don't understand the exact mechanism," Mirmirani says. "There's a lot of thought about whether hormones during pregnancy can alter the shape of the hair follicle. The shape of the follicle dictates the shape of the hair fiber."Another site at kidshealth.org adds that hair grows faster during pregnancy. And in more places -- on the face, belly, back and nipples. The main culprit to all this growth is the hormone estrogen, plus increased blood circulation and a more hyperactive metabolism.
So during pregnancy, when it comes to the hair on your head anyway, most women experience nine months of good hair days.
Sadly, however, it doesn't last. The whattoexpect.com web site puts it like this:
Your good-hair-day run ends with delivery, when the normal daily hair loss that's suppressed during pregnancy resumes with a vengeance. Once your baby is born, all that hair that didn't fall out during pregnancy will.