Development at Fifteen Weeks

You may be able to feel movements as baby kicks, flails, twists and turns (but don't panic if you don't yet). She can also grasp, squint, frown, grimace and maybe suck her thumb!
Your baby's legs have grown longer than the arms and the body is now longer than the head.
And you'll be happy to note that he is moving those arms and legs often!
His skin is very thin -- so thin blood vessel are visible. It's covered by a fine, soft layer of hair called lanugo. Lanugo comes from a Latin word meaning "down." This hair is thought to help insulate your little boy.
The three tiny bones in his middle ear have begun to harden. The auditory centers in your baby's brain haven't developed yet, so she might not really understand what you say but her hearing capacity is in the process of developing.
Fingernails and toenails are growing.
Eyebrows are beginning to grow and even the hair his head is sprouting. It will probably change color and texture after birth.
All this and your little one is an amazing 3.98 inches (10.1cm) long and may weigh 2.47 ounces (70gm).