I’m going to be controversial here - I hate this image. Yes, I said it. I hate this image… you might be wondering why and questioning my strong reaction to something that seems to be perpetually presented on social media and is reposted by many birth workers, but here is my reason for such a passionate viewpoint.
An image that shows the measurements of a circle from 1 – 10 cms and is used to demonstrate how ‘big’ a woman can open to let her baby out, is seen by many as a positive thing. I am not disagreeing that it is beneficial for women to understand their body makes space and room for the baby and that this space, which is 10 cms at its fullest, enables the baby’s head to pass through then, down and out the birth canal. I agree that showing the space with reference to a baby’s head and talking about how their skull is soft and malleable is comforting to know for many women. However, this image also suggests that your cervix (not vulva as some may think this represents) is a hole that just opens to let baby out, like a wrench clicking, minute by minute, hour by hour until it reaches full width. It’s images such as this that feed our cervical centric culture, encouraging women to fixate on dilation when in labour.
This fixation on dilation and the size of the space doesn’t accurately enable women to understand or visualise what the process is. Your cervix isn’t a hole that stretches or opens as images showing 1-10cm imply. The cervix doesn’t dilate out, it moves up, getting out of the way and becoming part of the uterus. In the third trimester, the cervix will begin to soften and thin, in a process called effacement. As part of this, the cervical opening also begins to widen. Then, as surges are taking place during the first stage of labour (sometimes without mothers even realising), the muscles of the uterus are all moving up, and as they do so they are slowly collecting at the top in an area called the fundus. As the muscles move up to the top they pull the now thinned cervix up and over the baby’s head. This is what creates the opening, with help of pressure from your baby’s head.
Dilation is more like pulling on a polo neck jumper. To happen effectively and efficiently it requires the pressure of your baby’s head along with the pull up of your uterus muscles, much like using your head to push, while your arms pull that jumper over and down. This is why procedures such as stretch & sweeps are regularly unsuccessful (only 1 in 8 resulting in onset of labour), often causing the surges but without the baby being ready to be born – IE not having the added pressure of their head to actually continue the opening up process. It is when this happens that VE's can be helpful, if things are really not progressing, these examinations that can identify if the baby’s head if flexed or in the favourable position, OA
Returning to the limited benefits of thinking in 'cervical dilation' measurements, it is actually the purpose of early labour for the muscles to collect at the top of the uterus and to build the fundus. It’s all these muscles moving up and gathering at the top of the uterus that will push the baby out. In a reflex call the fetal ejection reflex, the uterus will literally eject the baby and push it down and out - yep cool huh? This, along with the baby moving and turning to navigate the birth canal is how we give birth. However without that collection of muscles at the top there is no power to get baby out.... Measuring dilation can possibly give a, very rough, idea of how thick the fundus is becoming because of the lack of cervix that can be felt, but it also has to be taken into consideration that the cervix is temperamental and can be manipulated without having any effect on the rest of the uterus. In fact, research shows that two people measuring the dilatation of a cervix will only get the same reading 42% of the time, so depending on who is conducting the VE you might receive a completely different figure. *** ( Buchmann EJ 2007)
Imagine if instead of sharing information about the size of space in a cervix we educated women on the behaviours, noises and movements they are likely to experience at each stage of labour so that they and their partners could be more aware of how the labour is progressing without the interference of internal examinations. Add to that, education on the purple line that can be seen or the movement of the Rhombus of Michaelis during labour - that could be powerful for women to know about.
If we all tried to reduce the fixation on cervical measurements, this could result in more women following their body and their baby’s cues during labour, which dare I say it, may lead to less intervention as a result. Who knows?