Labor prior to 37 weeks of gestation is considered preterm. True preterm labor means that preterm contractions are accompanied by cervical dilation. This condition is common; about 12 percent of pregnancies in the United States are preterm. If you start having persistent contractions, especially if they become more and more painful, your doctor will need to monitor you for preterm labor. Usually this involves observation in the hospital, monitoring of your baby and contractions, ruling out various infections that could contribute to this, and deciding on whether there is a high risk of preterm delivery.
In many cases, depending on gestational age, a cervical length measurement is obtained to see if your cervix is starting to shorten, which happens with contractions. Also, there is a test called fetal fibronectin that can be used to predict the likelihood that preterm contractions are not going to lead to true labor. It is very reassuring when it comes back negative; it means that you are not likely to have a preterm delivery in the next two weeks.
If your doctor deems it necessary, you may need to be given a tocolytic agent (a medication that can help slow down or stop contractions). Steroid injections are also given between 24 and 34 weeks in order to help with baby's lungs and brain if preterm delivery actually occurs. Antibiotics are also usually administered initially while waiting for the group B Streptococcus culture to come back (see below).