ABSTRACT
When labour begins, uterine contractions usually increase gradually in both strength and frequency; they may not reach maximum effectiveness until approximately 3 cm of cervical dilatation is reached. Up to that point, labour can be described as in the latent phase; after that, it is regarded as in the active phase. After 3 cm of cervical dilatation, progress should be relatively rapid until 8-9 cm, when there is a slight slowing until full dilatation is reached.
