Why is the cervix open?

When your cervix opens, it means you are about to give birth, which is commonly known as cervical dilation. At this time, mothers will feel abnormal pain in their abdomen, and sometimes the pain needs to continue for several hours before their cervix can open to a certain size, so that they can successfully give birth to the baby in their belly, so you should pay more attention to observation.

The professional name for opening the cervix is ​​cervical dilation. The cervical canal of women is a muscular tube about 2 cm long, connected to the vagina on the outside and the uterine cavity on the inside. When a pregnant woman is about to give birth, her uterus contracts regularly, pulling on the uterine muscles and surrounding fibers at the internal os of the cervix. In addition, the amniotic fluid sac is wedge-shaped in front of the fetal presenting part, causing the internal os of the cervix to expand upward and outward, and the cervical canal gradually shortens until it disappears. The external os of the cervix is ​​usually only the size of a fingertip. As labor progresses, the external os of the cervix expands to a diameter of 10 centimeters, allowing the full-term fetal head to pass through. This process is called cervical dilation.

The process of cervical dilation is relatively slow. Usually, the cervix gradually flattens in the second week after the 9th month of pregnancy, which is also the process of cervical formation. Your cervix will dilate to 10 centimeters when your baby is born. It will be slow at the beginning. It takes an average of 8 hours from labor to 1 centimeter dilation, and an average of 4 hours from 6 centimeters to 10 centimeters. Generally speaking, some medication will not be used to treat the pain until the cervix is ​​dilated to centimeters.

This indicates that the mother has entered the active phase of labor. The cervix has dilated to 6 cm, the cervix has become soft, thin, and elastic, and each contraction is 2-3 cm apart. After delivery, the cervix will gradually dilate with regular uterine contractions. The first stage of labor is divided into two phases according to the degree of cervical dilation: the latent phase and the active phase. The latent phase is from regular uterine contractions to 6 cm cervical dilation, and the active phase refers to the period from 6-10 cm cervical dilation.

It should be noted here that the speed at which the cervix dilates is different between primiparas and multiparas. For primiparas, the cervix shortens and flattens first, and then the cervix dilates; while for multiparas, the cervix shortens, flattens, and dilates at the same time. Therefore, the progress of multiparas is obviously faster than that of primiparas, which is also the main reason why the first stage of labor progresses differently between primiparas and multiparas. During the latent period, the cervix opens slowly, but during the active period, it opens much faster.

The incubation period for primiparas is about 8 hours, and that for multiparas is faster than that for primiparas, but there are large differences between individuals, and the length of the incubation period varies from person to person, ranging from tens of minutes to several hours. The active period of a primipara lasts about 4 hours. After a multipara enters the active period, she should prepare for delivery, because the cervix of a multipara will usually fully dilate soon after entering the active period.