Answer the following question given this paragraph: 

Near the time of birth, the amniotic sac breaks in a gush of liquid. Labor usually begins within a day of this event. Labor involves contractions of the muscular walls of the uterus. With the mother’s help, the contractions eventually push the fetus out of the uterus and through the vagina.


Q: What helps push the fetus from the uterus during birth?


A:
contractions