</span><span>Under the effect of contractions, the cervix opens. Cervical dilation period includes two phases:
The lag phase, which corresponds to the deletion and early cervical dilation up to 3 cm. It takes about 7 am and 5 am in primiparas in multiparas. The active phase, which corresponds to the cervical dilation of 4 to 10 cm. The average length of cervical dilatation is variable.</span>
Answer: Time dilation is the difference of time between two events. This events are measured by two different observers that are moving relatively to each other or that are present two different places.
