Crown to rump, your baby is around 3 and a half inches / 9 centimetres long and weighs one and a half ounces / 43 grams. The body is now growing faster than the head. This week, its parchment-thin skin covers itself with lanugo (ultra-fine, downy hair that usually disappears before birth). Though eyebrows are beginning to grow and the hair on top of the head is sprouting, this hair may change in both texture and colour after birth. About now, the fetus can grasp, squint, frown, and grimace. It may even be able to suck its thumb. Researchers believe these and other movements probably correspond to the development of impulses in the brain.