Chapter 16: The Second Stage of Labor

DEFINITION OF THE SECOND STAGE OF LABOR

The second stage of labor lasts from the end of the first stage, when the cervix has reached full dilatation, to the birth of the baby. This is the stage of expulsion of the fetus. The duration of the normal second stage of labor is influenced mainly by two factors: parity and the presence of an epidural. The median durations of the second stage are given in Table 16-1, but there is a large range in duration.

Second Stage in the Absence of Epidural Analgesia

In the absence of an epidural, a woman will often experience more intense and frequent contractions as she approaches full dilatation. This is sometimes referred to as transition. The patient should be discouraged from pushing (bearing down) before full dilatation. Breathing deeply and slowly during each contraction may help in coping with the pain. Once the head reaches the perineum, the maternal desire to bear down may become difficult to resist. The following are possible indicators of the onset of the second stage, although they are not exclusive to the second stage:

1. There is an increase in bloody show.

2. The woman wants to bear down with each contraction.

3. She feels pressure on the rectum accompanied by the desire to defecate.

4. Nausea and retching may occur as the cervix reaches full dilatation.

The cervical dilation and station of the presenting part must be confirmed by vaginal examination.

Second Stage with Epidural Analgesia

In the presence of epidural analgesia, the duration of the second stage is approximately twice the duration of a non-epidural second stage. This is because the neurohumoral reflex of oxytocin release due to the perineal pressure of the head, which assists the urge to bear down, may be interrupted. In addition, the incidence of instrumental vaginal delivery, but not cesarean section, is also increased twofold. For this reason, it is important for the care provider to have an understanding of how to best manage the second stage under epidural.

Phases of the Second Stage of Labor

There are two phases of the second stage of labor, the passive stage and the active stage.

Passive Phase of the Second Stage

During the passive phase of the second stage, the cervix is fully dilated, but there are no voluntary or involuntary ...