Signs of early labor include:

• Dropping
• Cervical dilation
• Braxton-Hicks contractions
• Ruptured membranes

Dropping
The fetus drops into the pelvis in a head down position.

Cervical Dilation
During pregnancy, the cervix remains tightly closed. In order for labor to begin, the cervix must begin to open. This is referred to as cervical dilation. Before the cervix begins to open, a plug of mucus that is blocking this channel must be pushed out. If the mucus is stained with blood, passing the plug may be called bloody show. Following the passage of a mucus plug or bloody show, cervical dilation starts. The cervix must open more than 10 centimeters before the baby can pass through it. First time mothers tend to dilate more slowly than mothers who have delivered a baby in the past.

Braxton-Hicks contractions
These contractions have been painless for the past several months. At this point, they become stronger and cause pain. The pain seems to come from within the pelvis, groin, or lower back. Many first time mothers are fooled by these contractions. This is why they are often referred to as false labor. False labor contractions have no pattern, change in strength, are located in the lower abdomen, and may change with activities, such as walking or resting. True labor contractions are regular and slowly build in strength. They are often felt in the abdomen and back, and do not go away with walking or resting. Time how long your contractions are from beginning to end, then time how far apart they are from the beginning of one contraction to the beginning of the next one. Write the information down in a logbook, so that you can track your progress.

Rupture of Membranes
A strong membrane makes up the amniotic sac, which contains the fetus and the amniotic fluid that surrounds the fetus. When the membranes rupture, amniotic fluid leaks from the uterus. This may be confused with bloody show and a mucus plug. Your doctor may perform tests to confirm that you have ruptured membranes. The membranes usually rupture after labor contractions have started. In about 1 out of 5 women, the membranes rupture before the onset of labor contractions: this is called premature rupture of membranes. Once the membranes rupture, labor is starting: you need to see your doctor immediately. More than 90% of women go into labor within 24 hours after the membranes rupture.