The average size for the fetus is about  3 1/2 inches in length  – imagine the dimensions of a lemon – and it weighs a little over 3 ounces. The body, at this stage, develops more than the head. Your baby will begin to make suction movements with its mouth and might even be able to stick its thumb in it – fingers crossed this super cute moment is caught on the ultrasound! Certain things like frowning the forehead or moving the little hands are not voluntary actions, but rather reflexes. Remember: the brain is in total development. On the 14th week, the eyes and the ears are positioned correctly on the head. And the skin is covered in lanugo, a very thin and soft hair that will be shed during the sixth month of gestation.