What is a contraction?
Without contractions, there is no labour, so what it a contraction and how do they work?
For labour to happen the cervix needs to be ready and the long muscles of the uterus need to shorten to pull up the cervix so it can dilate. When your cervix is fully dilated, contractions become more expulsive and they push baby out of the womb.
Uterine contractions in labour are needed to open the cervix and for birth they are needed to guide a baby out of the womb, through the pelvis and down the vagina.
Here’s a quick guide to how a contraction works
The hormone oxytocin is needed to create and regulate contractions
There are oxytocin receptors on the uterus, which responds to the oxytocin and creates a contractions
contractions start at the fundus, which is the top of the uterus, and then move down towards the cervix
during a contraction, the muscles of the uterus tighten, which slows the oxygen reaching your baby. This is why contractions are not continuous – the pauses in-between contractions give your baby the time to ‘breathe’ normally before the next contraction
the muscles of the uterus relax in-between contractions so when each one starts, the tightening builds up – it reaches its peak and then the muscles start to relax again
most of the contractions in established labour will be about a minute long – the pause in-between is individual to your labour
the longest contractions will be towards the end of labour, when you are almost fully dilated. This is the transition phase between labour and birth, when your contractions start to change what they are doing and the muscles of the uterus are getting ready to move your baby down and out of the womb. These contractions could be around 90 seconds long with a similar pause in-between.
Oxytocin is the magic hormone because it is essential for labour but it is influenced by how you are feeling. So, what can boost the release of oxytocin?
Ultimately you need to feel safe in labour and that can come from:
being informed and understanding what needs to happen during labour and birth
feeling listened to and supported
being able to move as you need to
privacy, quiet and calm
being as comfortable as possible
feeling connected with touch and eye contact
being able to relax with and in-between contractions
And what can interfere with oxytocin production and your contractions?
being alone and feeling vulnerable
feeling frightened and overwhelmed
feeling unsupported and not listened to
bright lights, noise and interruptions
travelling from home to hospital in labour
too many people and feeling watched
feeling uncomfortable and unable to use positions and gravity
I just want to add here that oxytocin given by a drip to induce labour is not the same as natural oxytocin. The receptors on the uterus may not respond well to synthetic oxytocin and the contractions can be too powerful, which can be difficult for a baby to manage - this is why babies are continually monitored when an oxytocin drip is in place. It can also mean that the contractions created by the drip aren’t effective so feeling safe, informed and comfortable during an induction is crucial so you can create your own oxytocin to boost contractions.
Expectations of contractions
The expectation is that there is one pattern of contractions that every woman needs to achieve and experience. The truth is that every labour is unique to each individual combination of woman and baby.
In a textbook labour, contractions grow in intensity and get closer together so there are 4 in 10 minutes but for some women their contractions remain 5 minutes apart but they are effective and strong and doing their job. Labour is individual.
What do contractions look like?
As a very simple guide…
mild contractions at the beginning of labour can be noticeable but not all-consuming – women tend to be able to continue to talk and do as normal
as contractions begin to intensify they demand more attention and a labouring woman will start to focus on them and to work with them with positions and breathing
with the strong, regular contractions of established labour, women tend to become quiet and focused and more into their own world, being less responsive with brief communication
as contractions become more expulsive for birth, women become more alert and responsive after being quiet and trance-like during labour
after giving birth, contractions will be needed to help with the placenta. The contractions will stop when the placenta has been delivered
If you are reading this to prepare for your own labour, make notes and jot down your questions so you can personalise this information for you - feel free to comment and ask any questions underneath this post.
And remember, labour and birth is unique and there isn’t one right way of doing it for everyone - this is something we will be focusing on with the weekly posts.
Coming up this month:
birth support
labour & birth essentials
postnatal overview
birth recovery
unsettled babies
the 4th trimester