First, the cervix must efface or become very thin. Effacement typically preceeds dilation. The onset of uterine contractions assists in dilation, especially. True labor is distinguished from false labor when contractions appear at regular intervals and increase in strength, duration, and frequency over time. The beginning of labor usually is announced by the dissolution of the mucous plug from the cervix and the loss of amnionic fluid.
Contractions are relatively weak, short, and distant in appearance at the beginning of labor.
Labor for a first birth often lasts up to 24 hours with the most intense contractions occurring toward the end. Imminent birth is recognized with contractions occurring about 2-3 minutes apart and lasting up to a full minute. When the fetal head crowns at the vaginal opening, most women experience strong urges to push down and propel the fetus out of the birth canal. D. Delivery 1. Delivery involves the actual birth or expulsion of the fetus from the uterus.