Dirty dirty mattress van

My wife and mother-in-law noticed a dark spot about the diameter of a pencil eraser in the center of the mattress. It was surrounded by a fainter ring a little smaller than a dime. It appears to be a menstral stain. We later noticed this whole thing was surrounded by yet another, fainter ring about a foot in diameter. My wife guessed that it was a water stain from when the tried to clean the mattress. There were also dark hairs on the mattress.