Tightening of the uterus that occurs on and off during pregnancy and becomes more regular, closer together and stronger during labor.

A warm bath, gentle motion from a rocking chair or deep breaths through the contractions can help control pain. Birthing classes also may offer tips.

See a health care professional right away if:

• Six or more contractions an hour before 37 weeks of pregnancy that last one minute and don't ease with rest, drinking fluids or lying on the side.
• Clear fluid or bleeding occurs with contractions.
• Active labor starts or a health care professional says to go to a hospital.

Make an appointment to see a health care professional if:

• Not sure what the contractions are.