The words cervix and cervical dilation are very frequently used by doctors during pregnancy. Have you ever wondered what cervical dilation is and what role it plays in your pregnancy or delivery? Are you aware of the dilation symptoms to watch out for or what to do next? Not too sure? Don’t worry, we are here to guide you.
The cervix is an organ that connects the uterus to the vagina and serves as a passage during childbirth. The cervix remains closed throughout the pregnancy and starts opening up as the delivery date approaches. The cervix, towards the end of the pregnancy, will start thinning and start opening up to let the baby through. This process of opening up is cervical dilation.
No. Cervical dilation is very different from cervical effacement. Effacement is the ripening of the cervix, where it thins, softens and becomes shorter, getting ready for dilation. The next step is cervical dilation, where the cervix starts opening up.
While cervical dilation is measured in centimetres, effacement is measured in percentages. When effacement reaches 100%, it means the cervix cannot become thinner or softer any further. Though dilation and effacement go hand in hand, some women can experience it differently. Some women may experience effacement but no dilation or vice-versa. This is very common and nothing to worry about.
Ideally, cervical dilation should start when it is time for the baby’s delivery. Dilation can start just when labour starts or even weeks before labour. Doctors will start checking for and measuring dilation if any, from week 36 onwards. In case of complications, preterm delivery or a history of miscarriages, the doctor can check for effacement and dilation a few weeks earlier too.
Complete dilation of the cervix happens when it reaches 10 cm. Different women will take different time to progress to a full dilation. While some women may reach full cervical dilation within hours, some can take many days.
It is quite normal to record a cervical dilation of about 1 cm around the 37th week and not see any progress even by the 40th week. There is nothing to worry about. The dilation may start progressing only after labour starts. As mentioned earlier, it is very different for every pregnancy.
The rate of cervical dilation and the extent of dilation in a pregnant woman depends on various factors including the following:
● Medical history of the expecting mother – In case of high blood pressure or if the mother has given birth before, cervical dilation can progress quickly.
● Pelvic anatomy – If the pelvis is too small in comparison to the baby, or has other anomalies, it can slow down or even arrest the cervical dilation. Some cases may require medical intervention to help the dilation progress further.
● The size of the fetus or baby – If the baby is too small, delivery can be quick. Similarly, if the baby is on the bigger side, labour and dilation can take more time.
● Position of the fetus around labour time – If the baby is in a breech position, cervical dilation can take time. The baby’s head does not “fix” into position or start pushing through to help the cervical dilation progress.
The cervix should remain closed with the help of the mucus plug until it is time for labour. However, in some cases, cervical dilation can start earlier and may require medical intervention to prevent early delivery or any complications to the pregnancy.
Cervical insufficiency is a condition where the cervix starts dilating prematurely. It can start dilating as early as the second trimester itself. This can happen in case of previous pregnancy losses, past surgeries or some disorders. In many such cases, the doctor may prescribe progesterone supplements to help keep the cervix closed or even perform a minor surgery known as cervical cerclage. Through this procedure, the doctor will make sutures around the cervix to prevent the cervix from opening further, which can lead to preterm birth.
What happens if the cervix does not start dilating even after 40 weeks of pregnancy? What if the expecting mother starts experiencing contractions but her cervix does not dilate?
● If the baby is too big for the mother’s pelvis or is in a breech position, it can slow down or even arrest the dilation.
● If contractions are not strong enough, dilation may not progress.
● It could be false contractions.
● Arrest of labour in stage 1 – may require medical intervention.
● The doctor may induce dilation and labour manually or surgically.
During pregnancy, it is very important to understand and identify cervical dilation. A cervical dilation measurement of 0 cm means the cervix is fully closed. The cervix slowly starts dilating and reaches full dilation when the cervical dilation measurement is 10 cm. Remember, if you are not too sure, it is always safer to get a medical opinion than self-diagnosis. Some women may not realise they are in labour until it is very late, and this can lead to unnecessary complications.
1. Bloody Show – The most common symptom of cervical dilation is the discharge of the mucus plug, which is mostly accompanied by some blood. If you notice a little blood along with your vaginal discharge, it could be the mucus plug and dilation may be starting soon.
2. Vaginal Discharge – AN increase in vaginal discharge or a watery discharge could be your water breaking and the onset of cervical dilation.
3. Discomfort/Pain – If you experience sudden or constant dull pain around your lower back or an increase in pelvic pressure, it could mean labour is starting soon.
4. Contractions – If dilation increases or labour starts, you may experience contractions.
Dilation of the cervix before the baby is fully mature (around 38 weeks) is a cause for concern. In case of incompetent cervix or cervical insufficiency, the risk of a miscarriage or premature birth is high.
Cervical dilation is a part of pregnancy and can be different for different women. It can be different for every pregnancy. Anytime dilation starts – be it early in the pregnancy or around the due date, it is always safer to go for a check-up. The doctor can then decide if it isn’t something to worry about or if it requires any medical intervention.
Different women experience it differently. Some women don’t even realise they are dilated until the bloody show or the doctor manually confirms dilation. Some women can experience intense and painful contractions as labour progresses along with the dilation.
