The diagnosis of labour is made when these criteria are met:
- history of regular, painful contractions: in well-established labour, a uterine contraction lasts for about 50-60 secs and occurs every 2-4 minutes.
- a show or breaking of waters
- progressive dilation of the cervix.
Dilation of the cervical os proceeds at about 1 cm per hour. The duration of this stage is influenced by uterine activity, fetal attitude and cephalopelvic relationship. It is said to be essentially independent of other factors: parity has only a minor effect; and race, multiple pregnancy and analgesia are unimportant.
The partogram should be started when labour is diagnosed.
- latent first stage of labour - a period of time, not necessarily continuous, when:
- there are painful contractions, and
- there is some cervical change, including cervical effacement and dilatation up to 4 cm
- established first stage of labour - when:
- there are regular painful contractions, and
- there is progressive cervical dilatation from 4 cm
- duration of the first stage
- women should be informed that, while the length of established first stage of labour varies between women, first labours last on average 8 hours and are unlikely to last over 18 hours. Second and subsequent labours last on average 5 hours and are unlikely to last over 12 hours
- definition of delay in the established first stage
- diagnosis of delay in the established first stage of labour needs to take into consideration all aspects of progress in labour and should include:
- cervical dilatation of less than 2 cm in 4 hours for first labours
- cervical dilatation of less than 2 cm in 4 hours or a slowing in the progress of labour for second or subsequent labours
- descent and rotation of the fetal head
- changes in the strength, duration and frequency of uterine contractions.
Reference:
- NICE (September 2007).Intrapartum care.