Labor Contractions
During contractions, the abdomen becomes hard. Between contractions, the uterus relaxes and the abdomen becomes soft. The way a contraction feels is different for each woman, and may feel different from one pregnancy to the next. But labor contractions usually cause discomfort or a dull ache in your back and lower abdomen, along with pressure in the pelvis. Contractions move in a wave-like motion from the top of the uterus to the bottom. Some women describe contractions as strong menstrual cramps. Unlike false labor contractions or Braxton Hicks contractions, true labor contractions do not stop when you change your position or relax. Although the contractions may be uncomfortable, you will be able to relax in between contractions.
Source: http://www.webmd.com
