a. First Stage of Labor.

The first stage of labor is referred to as the “dilating” stage.

It is the period from the first true labor contractions to complete dilatation of the cervix (10cm) (see figure 2-2). The forces involved are uterine contractions.

The first stage of labor is divided into three phases:

(1) Latent (early) or prodromal.

(2) Active or accelerated.

(3) Transient or transitional.

b. Second Stage of Labor.

The second stage of labor is referred to as the “delivery or expulsive” stage. This is the period from complete dilatation of the cervix to birth of the baby. The forces involved are uterine contractions plus intra-abdominal pressure.

c. Third Stage of Labor.

The third stage of labor is referred to as the “placental” stage. This is the period from birth of the baby until delivery of the placenta. The forces involved are uterine contractions and intra-abdominal pressure.

d. Fourth Stage of Labor.

The fourth stage of labor is referred to as the “recovery or stabilization” stage. This period begins with the delivery of the placenta and ends when the uterus no longer tends to relax. The forces involved are uterine contractions