Limited control. At 2 weeks a baby has control of it's facial muscles & jaw, can lift his/her head & turn side to side. The rest of babies movements are rather random. The brain sends out random messages to move the body parts through their natural range. This helps preserve muscle size & tone until the baby develops muscle control. There are also random reflexes that set off patterns of movement.
Smoother. Movements gradually become smoother and more controlled. Lifts chin for a few seconds when lying on tummy. Cannot support head without assistance. Grasps whatever is placed in hand.