Opening of the cervix or dilation during labor

What do we mean by dilation?

The uterus is made up of two parts, the body in which the baby develops, and the cervix. Well closed throughout the pregnancy, the cervix will have to open at the time of childbirth to allow the passage of the baby by natural means. This is called dilation. This can only take place in the presence of a motor: uterine contractions. To assess the dilation, the doctor or midwife performs a vaginal touch. This gesture makes it possible, among other things, to locate the neck and to measure its opening diameter which varies from 0 (closed neck) to 10 cm (complete dilation).

Cervical dilation: complex mechanisms

Several events accompany dilation. First of all the neck will lose length until it is completely erased (going from 3,5 cm to 0) then it will change consistency and soften. Finally, his position, which was posterior (back), will gradually become centered. These mechanisms often begin at the end of pregnancy (this is called maturation) and will accelerate during the various childbirth phases.

Cervical dilation: a process that takes time

It takes several hours for the cervix to fully open. Up to 5 cm of dilation, it must at the same time disappear, and this first part is often long, especially in mothers who give birth for the first time. Then the dilation will continue at the same time as the baby’s head (or buttocks) will engage and then descend through the pelvis. From time to time, the cervix does not expand or stops opening along the way. This is called cervical dystocia.

Why does cervical dilation not work?

The reasons are numerous and involve several parameters. If the uterus is a little lazy and the contractions of poor quality, the dilation will not be done correctly or much too slowly. Sometimes, despite good contractions, the cervix refuses to open. It can come from the cervix itself. It may be immature, present a malformation or have been damaged by an intervention (electrocoagulation, repeated curettage, etc.). In other circumstances, it is the baby that is involved. In order for dilation to progress, the baby’s head must press on the cervix. The more she asks for it, the more it will open. And the more it opens, the faster the descent will be. Everything is connected. If the baby is too big compared to the mother’s pelvis, it blocks. This is also the case if the baby positions his head badly or if the head is not flexed enough.

What medical solutions to dilate the cervix?

In the presence of insufficient contractions, the artificial rupture of the bag of water using a small forceps often allows to obtain a better uterine contractility. If despite this the dilation does not progress, we can give the mother an infusion of oxytocics. These substances mimic the effect of natural hormones and act directly on the uterus by causing it to contract. When the contractions become painful, many moms turn to an epidural. 

In addition to its pain-relieving effect, it often allows the cervix to “let go” and to open more quickly. Sometimes midwives use an antispasmodic which they add to the infusion. This product can help relax a neck that is a little too toned.

Softer ways to help the cervix

Some obstetric teams use acupuncture. This traditional Chinese medicine consists of stimulating particular points of the body using very fine needles. It gives good results on recalcitrant passes. Usually, midwives, specially trained in this technique, take care of it. Some even use it at the end of pregnancy to prepare the cervix for childbirth. Homeopathy also has its followers and is safe for the baby. Moms-to-be take the treatment one month before childbirth and as soon as labor begins to improve dilation.

Namely

It is sometimes a question of position. The one lying on the back is not the most favorable to allow the baby’s head to progress and to press on the neck. A little help can be to put the mom on the side, theask you to walk or sit with your legs bent well.

Cervical dilation: what if it doesn’t work?

Normally the dilation should continuously progress. It is very variable from one mother to another, but the cervix generally opens from 1 cm / hour to 5 cm, then 2 cm / hour thereafter. The problem can arise right from the start (onset dystocia). This is often the case when a decision is made to induce before the time of delivery and the cervix is ​​not sufficiently “ripe”. To obtain the maturation of the cervix, the doctor uses a gel which he applies directly to the cervix. Several hours are then necessary for the dilation to begin. During labor, dilation may stagnate, sometimes for several hours. Until a few years ago, medical teams considered that if the dilation had not progressed for two hours despite good contractions, they had recourse to Caesarean. Indeed, the use of forceps or spatulas can only be done if the cervix is ​​fully dilated and the baby’s head is lowered. Today, this “work stagnation” is considered “normal” for up to 3 hours. And the dilation resumes afterwards.

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