Labour is traditionally divided into four stages:

The first stage of labour.
The second stage of labour.
The third stage of labour.
The fourth stage of labour.

First stage of labour

This stage is from the onset of true labour till full dilation of the cervix. During pregnancy, the cervix is thick and long. As the first stage of labour thinning and softening of the cervix will take place this is known as effacement. Also, the diameter of the cervix increases up to 10cm letting the baby come out of the uterus this is called full cervical dilation.

Average duration of 1^ststage of labour 12 hours in primigravid and 7 - 8 hours in multigravid mothers

The first stage of labour is further classified in two based on cervical dilatation:

The latent phase is the period between the start of regular rhythmic contractions up to cervical dilatation of 3 cm. In this phase, the contraction is not painful, strong and the cervical dilation is slow.
The active phase starts as the cervix dilates 4 cm till fully dilated. At this phase, the contraction becomes more regular, frequent and strong. The expected cervical dilation ranges from 1.2 cm -1.5 cm/hour with at least 1cm/hour cervical dilation in primigravid and 1.5 cm/hour in multigravid. This is the end of the first stage of labour. At this phase, plotting on the partograph will start at 4 cm of cervical dilation which you will learn later in this session.

Second stage of labour

This is from full dilation of the cervix to birth of the baby. After the cervix is fully dilated, the mother typically has the urge to push. Her efforts in "bearing down" with the contractions of the uterus move the baby out through the cervix and down the vagina. This is known as fetal descent. This may take 1 hour in those women who had previous childbirth and 2 hours in those women who did not give birth before.

Signs of the second stage of labour:

The mother wants to push.
Regular uterine contraction.
Anal and vulval gaping.
No cervix is felt on vaginal examination.
The head is seen on the vulva.
Sometimes sweating and defecation.

This stage is dangerous for the newborn baby. The fetus may die due to fetal distress.

Fig. 2.2. A fully dilated cervix is 10 cm in diameter.

Third stage of labour

This starts from the birth of the baby till expulsion of the placenta. At this stage, bleeding may occur if the placenta is not expelled with in 30 minute which is the ideal duration of the third stage of labour. At this stage, if the placenta fails to expel after 30 minutes, it is called retained placenta. This stage is dangerous for the mother because she may die due to bleeding.

Signs of placental separation:

There is a gush of blood.
The uterus is hard. round, movable and at the level of the umbilicus.
The cord seems to lengthen.

Fourth stage of labour

This starts from the expulsion of the placenta till one hour after birth. This is very crucial, and mothers need close monitoring as bleeding might occur if the uterus fails to contract and legate uterine blood vessels, monitor vital sign especially blood pressure and pulse rate closely. You will learn later in this module the kind of care you will provide for the four stages of labour, and their management will be discussed.