During the nine months of your pregnancy, your baby has been growing in your uterus. The uterus is a pocket made of very strong muscles which stretch as your baby grows. The neck of the uterus, called the cervix, opens into the vagina. During your pregnancy the cervix is thick and is closed with a mucous plug.
During labour, the muscles of the uterus tighten and relax to open up the cervix and help the baby move out of the uterus. This tightening is called a contraction
Labour is divided into three stages. By learning about and practicing breathing, relaxation, and other comfort measures, you can prepare yourself for all stages of labour.