Whether you're having your fifth baby or your first, deciding whether or not you're in labor can be confusing. There are only two real signs of labor:

1. Regular, strong contractions lasting 40 to 60 seconds and,
2. Cervical dilatation (the cervix opening to let the baby pass through). Dilatation is measured in centimeters, from 1 to 10.

The only sign you can actually use to evaluate your labor is the regularity of your contractions. When you get to the hospital, the doctor or nurse will confirm your "diagnosis" by examining you vaginally to see if your cervix is dilating. Is this the real thing? To decide, look for three things in your contractions. These are exactly the questions your doctor will ask when you call:

1. How far apart are they?
2. How strong are they?
3. How long do they last?

Measure the time between your contractions from the beginning of one to the beginning of the next. Your contraction begins when you feel your abdomen tightening, not when you first feel it start in your back.

Everyone's pain tolerance is different. Some people become hysterical over a hangnail, while others can smile from a bed of nails. Gauging your contractions by the degree of discomfort you feel can be unreliable. To determine how strong your contractions are, which means how hard your uterus is working, follow these simple guidelines:

1. Place your hand at the top of your abdomen, which is where your uterus contracts, even though you feel the sensation in your lower abdomen.
2. With your fingertips, press on your abdomen to feel how firm it is.

Mild contractions:

These contractions are slightly uncomfortable. They're probably not unlike the false contractions you probably experienced during your pregnancy. An easy way to measure their strength is to put one hand on your abdomen and the other on the end of your nose to compare the resistance. A mild contraction feels similar to the end of your nose. There's something there, but you can still push it in.

Moderate contractions:

These contractions make you frown and pay attention, but they're not too bad. When you check your abdomen for resistance, it feels more like your chin than your nose. It feels a little firmer, but not that much.

Strong contractions:

These contractions are toe curlers, unless you're the bed of nails type. You definitely have to stop what you're doing until they go away. They feel as firm as your forehead, just like a rock. You can't push your abdomen in at all.

Length of contractions:

To determine how long your contractions are lasting, start counting the seconds when you feel your abdomen tightening, not when you start feeling the discomfort in your back. Stop counting when your abdomen starts to relax, not when the contraction is totally gone. Errors in timing are common. You want to count only the number of seconds during which the baby's head is being pushed against the cervix and trying to dilate it.

Backache doesn't count because the contraction hasn't started working yet. When the uterus starts to relax, the pressure of the baby's head is also relaxing. The contraction isn't working anymore. Even at their longest and strongest, contractions usually last only 60 seconds.