Throughout the early, active and transitional phases of 1st stage, the uterine muscles contract and retract. Therefore, after each contraction, the individual uterine muscle cells become shorter, making the uterus smaller in size and pushing your baby down and out. During a contraction the uterus tilts forward and downwards. At the same time, the cervix becomes thinner, being pulled up and open (or 'dilating').
Labour contractions normally behave in a progressive way. They usually start off in prelabour being short (20-30 seconds), mild and irregular (or more than 5 minutes apart), changing as the labour becomes more established. In the early 1st phase, the contractions tend to become longer (40-70 seconds), more intense, and usually less than 5 minutes apart. However, some labours do not follow this pattern. Occasionally, a woman will have no build up, and at times she may labour until her baby is born with only moderate, 5 minutely contractions, that would normally be associated with prelabour, or early 1st stage.
The following information describes a range of contraction patterns, which are usually associated with the early 1st phase. It is meant as a general guide only, as some phases do not exhibit obvious changes. The descriptions given here, as well as for the other phases, should reflect the majority of labours.
Early 1st phase contractions may present as: