To time contractions, you’ll pay attention to and record two things:
• The time each contraction begins
• How long each contraction lasts
This will tell you the frequency and duration of your contractions. (Note: To find out how “far apart” your contractions are, measure from the beginning of one contraction to the beginning of the next—not the time between them.) Your OB will probably give you a guideline for when to call or head to the hospital (like, when contractions are 5 minutes apart and lasting 30 to 45 seconds). Keep track the old-fashioned way with a stopwatch and a piece of paper (if you’re really in labor, you’ll probably need your mate to help). Or, use our contraction counter. Either way, you’ll be looking for contractions that progressively last longer and come closer together. Each contraction might not be longer, or arrive sooner, than the one before it, but in true labor, a pattern will form over the course of a few hours.
— Excerpted from The Baby Bump: 100s of Secrets to Surviving Those Nine Long Months
Plus, More from The Bump: