Different women will experience different symptoms at the onset of labor. Some women may experience lower back pain or cramping similar to menstrual cramps. In some women, the amniotic sac ruptures early in labor with a sensation of fluid leaking either as a trickle or a large gush of fluid. Some women will lose the mucous plug that blocks the cervix with a brownish or red-tinged mucous discharge. Ultimately, as labor progresses, uterine contractions become more powerful and more frequent.