What triggers labor in a pregnant women?

What triggers them is a lot of things anything can really trigger them, they could be asleep and they just go into labor. What also causes them to go into labor is old tissue that is carrying the baby either dies and the baby sends out a message throughout the body saying that you are in labor.

The person who utilize the progression principle will keep adding the difficulty of the exercise that he's doing, while the person who does not, will only stay stagnant.  the person that utilize progression principle, will get a stronger endurance because now his body is conditioned to do harsher routines.{the answer was already on verified)