Labour is a physiological event that usually ends with the birth of a baby and expulsion of the placenta. While normal labour usually ends within 12 hours, labour may be prolonged in some cases. Prolonged labour can lead to serious maternal problems including:

Problems for the baby include:

These problems can be largely prevented by good management of labour.

LABOUR

Labour is the process in which uterine contractions lead to progressive dilatation of the cervix and delivery of the baby and placenta.

Suspect or anticipate labour if a pregnant woman has:

These symptoms are not, by themselves, diagnostic of labour. Confirm the onset of labour only if intermittent uterine contractions are associated with progressive changes in the cervix:

::	Cervical effacement: the progressive shortening and thinning of the cervix in labour; the length of the cervix at the end of normal pregnancy is variable (a few millimetres to 3 cm); with the onset of labour, the length of the cervix decreases steadily to a few millimetres when it is fully effaced
::	Cervical dilatation: the increase in diameter of the cervical opening, measured in centimetres (Figure 11.1).
Figure 11.1

First stage

In early labour (the latent phase), effacement and slow dilatation occur. Effacement is usually complete by the time the cervix is 3–4 cm dilated. After this phase, the cervix dilates rapidly (the active phase) until it is 10 cm (fully dilated). The latent phase and the active phase together constitute the first stage of labour.

Second stage

The second stage of labour begins after full cervical dilatation is reached. Fetal descent through the birth canal occurs towards the latter part of the active phase and after the cervix is fully dilated. Once the fetus touches the pelvic floor, the woman usually has the urge to push (the expulsive phase).

Fetal descent

Fetal descent may be assessed by abdominal palpation and vaginal examination

Abdominal palpation

Fetal descent into the pelvis may be assessed in terms of fifths of head palpable above the symphysis pubis (Figures 11.2–11.3):

Figure 11.2
Figure 11.3
::	5/5 refers to a head that is entirely above the inlet of the pelvis
::	0/5 refers to a head that is deep within the pelvis.

Vaginal examination

Fetal descent can also be quantified by relating the level of the fetal presenting part to a bony reference point in the maternal pelvis. Conventionally the ischial spines provide such a reference point (Figure 11.4: 0 = level of ischial spine).

Figure 11.4

Third stage

The third stage of labour begins with the delivery of the baby and ends with the expulsion of the placenta.