Having been in the delivery room twice, I can't even imagine being handcuffed or openly restrained while trying to deliver my children.  The pain of the first birthing was agony until some pain medication was put into my intravenous line, but my second child crowned while I was being wheeled into the delivery room and before I had been given any RX. My doctor was hurriedly taking off his street clothes to don his scrubs and a nurse was tryng to hold me down inn order to put RX into a line, which made the delivery even scarier. 

When you've supplied all the food and nourishment the baby-in-utero needs, and when the process of giving birth arrives, it takes everything you've got to push the baby out and into the world.  It's a mental, physical and emotional experience which brings you to your knees, and you scream and thrash out in order to separate yourself from the baby so that he or she can be born and LIVE!

Being restrained is an abomination and should be forbidden unless the patient is mentally unstable and  undermining the delivery and health of the baby.