When a woman’s cervix thins during labour it is referred to as effacing. When her cervix is opening it is called dilating.
These cervical changes can be measured by the caregiver doing an internal vaginal examination with their gloved fingers during labour, often referred to as a VE or vaginal examination, or perhaps an ‘internal’. During labour, vaginal examinations are usually carried out after a contraction finishes and when the woman says she is ready.
An internal examination procedure involves the caregiver putting on a sterile glove and often using an antiseptic cream, applied to the first and second fingertips.Their 2 fingers are then gently inserted into the woman’s vagina, so the caregiver can examine her cervix. The woman’s cervix is checked for the following:
- Dilation – or how open the cervix is. This is measured from 1 to 10 centimetres (10 cm being fully open or fully dilated).
- The consistency of the cervix. Is it soft, stretchy and yielding – often referred to as ripe or favourable. Or is it firm and tight rimmed often called unripe during late pregnancy.
- The position of the cervix. During pregnancy the cervix leans towards the back (or posterior) behind the baby’s head. This often makes it difficult for the caregiver to reach. As the cervix ripens (and during labour) it moves forward towards the front, making it more accessible for the caregiver and indicating progress is being made.
- The estimation of how far the baby’s head has come down into the pelvis. This is called the station and is measured from minus 3 (- 3), meaning the baby’s head is high and not engaged, to plus 3 (+3), where the baby’s head can be seen at birth. Most babies’ heads are at minus 2 at the beginning of labour and 0 to +1 when the pushing starts.
- The effacement. This is how thin the cervix feels and is measured in percentages from 0% to 100%. 0 % is when the cervix is long and thick, 100 % is when the cervix is paper thin, when most of it has been pulled up and absorbed into the lower segment of the uterine wall.
- How well the baby’s head is sitting on the cervix. The part of the baby ‘leading the way’ during labour is called the ‘presenting part’, which may be their bottom if in a breech position. The caregiver tries to estimate how ‘well applied’ the baby’s head or presenting part is to the cervix. A well applied head is regarded as being more efficient at dilating the cervix during labour.
- The position the baby is lying in (i.e. posterior or anterior). This can be felt if the cervix is more than 4 cms dilated but can sometimes be difficult to accurately determine.