Depending on which number baby this is, first baby or subsequent, the contractions you notice will seem to come sooner and be more intense than you knew in your previous pregnancy. Braxton-Hicks contractions are the ones which your uterus performs in preparation to deliver a baby. If the uterine muscles did not exercise they would be unable to perform during labor and delivery. These contractions can be very sporadic or seem as regular as labor contractions. It is often hard to distinguish between Braxton-Hicks, also called false labor, and the real contractions which are true labor.
Some factors do distinguish the two though.
Braxton-Hicks contractions will not do three things and that is get longer in duration, closer together and last for a longer time period. Real labor will have contractions that are progressive and unable to be halted. Braxton-Hicks contractions may come and go. They may persist for hours on end and then cease to exist at all. You may go to bed being sure you were in labor and wake still pregnant and wondering.