I'm due Monday and I've been having contractions all morning. At first they were 6-8 minutes apart and 45 seconds long for an hour. Now in the last hour and a half they have been coming consistently every 2 minutes, but they are only 30 seconds long. The end of this stage of labor happens when the cervix is fully dilated. Full dilation occurs at 10 cm. Contractions can strengthen in intensity as the cervix dilates from 0 to 3cm. Afterwards, they may lessen in intensity and are usually spaced 15 to 20 minutes apart. Each set of contractions can last up to 90 seconds. 1.