The cervix is the muscular channel or opening that runs between the uterus (or womb) and the vagina.
During pregnancy, your cervix plays a crucial role in protecting your growing baby. It’s closed to keep the baby safe inside the uterus. Then, in labour, contractions help your cervix to open, or dilate, to allow the baby to descend through the birth canal.
Cervical dilation is measured in centimetres to determine the different stages of labour. Your midwife or doctor might offer to perform a cervical check, and compare that information with the frequency of your contractions and stage of labour.
Stage 1 of labour is all about the cervix. Due to the contractions, the cervix opens until it reaches 10 centimetres. Early labour begins with irregular contractions, and the length of this stage varies from several hours to days (or even weeks), with the cervix going from closed to 3 cm dilated.
Once the cervix is dilated more than 3 cm, and contractions are strong and regular, labour is said to be established or active labour. As labour progresses, contractions become more painful, stronger, and around every 3-4 minutes. This is when the cervix will dilate from 3 cm to 7 cm.
This is followed by the transition stage, where the cervix continues to open until it is fully dilated. Now the first stage of labour is complete, your baby moves through the pelvis and is ready to be pushed out (stage 2). Stage 3 begins after your baby is born and finishes when the placenta and membranes have been delivered.
There are several signs that can tell you that you’re dilating without the need of an internal examination. Before you start dilating, your cervix must soften and shorten. This is called cervical effacement. If this isn’t your first birth, you might dilate and efface at the same time. How do you know if your cervix is dilating? Here are 5 signs that some women notice:
Sharp shooting pains felt in your vagina happens as women get closer to their due date and when cervical dilation begins. The pain is a result of your baby’s head pushing on nerves as it descends into the pelvis.
As your cervix begins to dilate, you may see a clear, pink, or brown discharge as a result of the mucus plug being released. This is an obvious sign that you’re dilating, but it’s important to seek medical advice about vaginal bleeding, particularly if you’re earlier than 37 weeks, the bleeding is bright red, or is more blood than mucus.
If you feel cramps just above your pubic bone, this can be a sign that you’re dilating. A dull ache in your lower back at regular intervals can be the start of labour contractions.
During early labour, you can probably talk and move around. As your cervix starts to dilate, you might stop talking and instead focus on your breathing and moving your hips. As labour progresses, you could find yourself making all sorts of sounds, and become unaware of what others are doing or saying around you.
The easiest way to assess dilation is for your midwife or doctor to do a cervical check. This isn’t always comfortable for women, particularly during active labour. It involves lying on your back, with your care provider inserting two fingers into your vagina. This check also helps them to assess the position that your baby is in.
It can be hard to tell when labour has started. If you’re not sure or are worried, call your hospital. They will ask you how and where you feel your contractions, how often they come, and how long they last for. If there are strong signs of labour, such as your waters breaking, regular contractions, or blood loss, contact your hospital anyway. When there is less than 3-5 minutes between contractions, it is time to go to the hospital.
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