A: Your doctor is the best person to provide the answer to your question. As a woman's body prepares for labor, the length of the cervix tends to shorten. This is called effacement. The consistency of the cervix becomes softer, and the position of the baby lowers in the birth canal. With the onset of regular uterine contractions, a cervix that is soft and effaced will begin to dilate. Try to notice whether you are having contractions (uterine tightenings). If you think you are having them more than four times an hour, call your doctor immediately.

On the other hand, if your cervix is long and firm, and your baby's position has not dropped, it's unlikely that a small amount of cervical dilation signifies early labor. Sometimes a woman's cervix dilates as a result of prior surgery on the cervix. Other times, the cervix dilates slightly when a woman has already had a baby.

Since your last appointment left you feeling nervous, I recommend that you call your doctor. Ask her to explain the significance of your cervical exam. She should tell you if she thinks that you're at risk for delivering early, and you should ask her for additional instructions on how to minimize the chance of preterm birth. If she doesn't feel that your last exam was suggestive of an early labor, it will be good for you to have some reassurance.