If you are being considered for induction, how ready or ‘ripe’ your cervix is will likely be assessed.
For most of the pregnancy the cervix lies towards the back of the vagina, behind the baby’s head. This is called a ‘posterior cervix’ and is often hard to reach by the caregiver if they are performing a vaginal examination. Near the time of labour and / or during prelabour and early labour, the cervix starts to move towards the front of the baby’s head. This is known as either a ‘central’ or ‘anterior cervix’ (depending on how far forward it has moved), and can usually be easily felt by the caregiver if being examined. The cervix also changes from being very firm and closed during pregnancy, to being soft to touch and slightly open just before labour starts.
The changes in the cervix as the pregnancy progresses is referred to as ‘cervical ripening’.The position, softness and openness of the cervix are usually assessed by the caregiver to determine what induction method will be used and / or whether the induction is likely to succeed. A more posterior, firmer and closed cervix has a higher chance of not responding to the induction, (meaning the induction is not successful and a Caesarean may be needed).
An ‘unripe’, or ‘unfavourable’, cervix is usually not ready to respond to labour contractions. Therefore, it is less likely to dilate in response to certain induction methods, (such as an oxytocin drip and breaking the waters). If the cervix does not dilate, the induction is regarded as unsuccessful, and a Caesarean would be required.
To increase the success of inductions, medications (called ‘prostaglandins’) have been developed, aimed at ripening the cervix before the oxytocin drip is given and the waters are broken. Prostaglandins are placed into the woman’s vagina (around her cervix), often helping the induction to be successful. In some cases, the prostaglandins start the labour on their own, without any further interventions. However, prostaglandin medications can have serious side effects and are not always the answer.
To help the caregiver assess the cervix ripeness a scoring system has been developed called the Bishop’s Score. The higher the score, the riper (or more favourable) the cervix is. Be aware that the interpretation of how the cervix feels (and therefore the score that is given) can vary from caregiver to caregiver. There are 4 categories in the scoring system and each category is given a score of 0 to 3. The scores are then added up and the success of and style of induction is assessed.
A score of 0-4 means the cerfix is unfavourable
A score of 4-8 means the cerfix is starting to become favourable
A score of 8-14 means the cervix is very favourable
|Dilation of the cervix||Closed||1-2 cms||3-4 cms||5+cms|
|Consistency of cervix||Firm||Medium||Soft||N/A|
|Position of cervix||Posteria||Midline/
|Effacement (thinning of cerfix)||0-30%||40-50%||60-70%||80%+|
|Station of head (how engaged)||-3||-2||-1 to 0||+1 to +2|