Pins and needles sleeping ?

If it is in one side of your hand only, it is probably carpal tunnel or cubital tunnel nerve pressure.

Cubital tunnel is the commonest at night, if you sleep with you arm folded (elbow bent), as the nerve runs around the outside of the elbow and gets stretched/compressed.

That causes your little finger side of the hand to tingle or go "dead".

If it's the index finger side, then that is probably carpal tunnel - where a nerve passes through the bones of the wrist & pinched if that is held bent.

If it's the overall hand, it is more likely circulation, as another answer says.

This is a common problem that can happen if something gets pinched while sleeping.  It could be caused by clothing, blankets, or how you are laying.

As you are waking up - pay attention to anything that feels like something is pressing on it.  Example - if your hand has pins and needles, then your nightshirt or your covers might have been wrapped to tight around your upper arm or you may have had your arm hanging off the bed or you might have been laying on your arm in a slightly odd position that pinched off some of the blood flow to the hand.  Wiggling returns the blood flow and stops the pins and needles.  

This is usually not a concern.  You would wake up from discomfort long before something like this would cause real damage.  .