Your mucus PKU can have blood in it, it can also be yellow or even green in appearance. A lot if the time the plug is a clear jelly like substance that can cone out in one big blob, or be lost little by little over the weeks- you may not even notice it.
If it has blood in it then this us a bloody show abd is more acurate in saying that labour is soon as it's shows your cervix is changing. The reason fir tge blood is because of the tiny little blood vessels in/on tge cervix... As your cervix changes you can rupture these....causing a bloody show (mucus plug mixed with blood).x