Prelabor contractions (also called "false" contractions):
Are irregular, following no discernable pattern for more than a few hours.
Are non-progressive: don't become stronger, longer, or more frequent.
Are felt most in front, in the lower abdomen.
Vary from painless to mildly uncomfortable; feel more like pressure than pain.
Become less intense and less uncomfortable if you change position or walk, lie down, or take a hot bath or shower.
Make your uterus feel like a hard ball.
Labor contractions (also called "real" or "true" contractions):
Follow a regular pattern. (Timing is seldom precise to the minute.)
Are progressive: become stronger, longer, and more frequent. The contractions get longer and the intervals between them shorter.
Are felt most in the lower abdomen and radiate around to the lower back.
Vary from uncomfortable pressure to a grabbing, pulling pain, which can usually be managed, even lessened, by conscious release of tension in the rest of your muscles.
Don't change if you lie down or change position; may be intensified by walking.
Are usually accompanied by a "bloody show."