Updated and edited: March 2015
This post has been inspired by conversations I’ve had with women about their experiences of induction. Induction of labour is increasingly common, yet women often seem to be very mis-informed about what it involves, or what was done to them during induction and why. For example, one woman was told by her obstetrician that induction involved him using a pessary to ‘gently nudge her into labour.’ Women need to be given adequate information in order to make birth choices. Practitioners need to give adequate information in order to meet legal requirements. I have written about the risks of induction in a previous post so will not repeat myself here. Instead, this post aims to provide some basic information about the process of induction – what is done and why. I would really appreciate input from readers about their experiences of induction – what was done, how it felt etc. I am hoping this post will be a resource for women who are considering induction, or are unsure about what happened during their induction.
In my old 1997 version of the ‘Midwives’ Dictionary‘ induction is ‘causing [labour] to occur’ ie. someone causes a labour to occur rather than allowing the baby/body to initiate labour. The dictionary goes on to say ‘this may be carried out when the life or health of the mother or fetus is in danger if the pregnancy continues.’ Of course this statement is open to interpretation and many inductions are not ‘medically indicated’ (link). However, I am not entering this debate here… I’m trying to stick to the process.
There are a few things you need to be clear about before choosing to be induced:
- That the risks involved continuing the pregnancy are greater than the risks involved in induction (risk is a very personal concept – see a quick word about risk).
- You are committed to getting this baby out. Once you start you cannot back out, and a c-section is recommended for a ‘failed induction’.
- You are not having a physiological birth. You have intervened and this intervention creates risks that require further monitoring and intervention. There is no ‘natural’ induced birth – vaginal birth maybe, empowering perhaps, but not physiological.
There are 3 steps to the induction process. You may skip some of the steps along the way, but you should be prepared to buy into the whole package when you embark on induction.
In a physiological birth the baby and placenta signal to the mother’s body that baby is mature and ready to be born (Mendelson 2009) – this starts the complex cascade of physical changes that results in the labour process.
Note: If your waters have broken naturally the term ‘augmentation‘ rather than induction is used to describe getting labour started. This is because it is assumed that your body has started the labour process itself. You can read more about this situation here.
Step 1: Preparing the Cervix
During pregnancy the cervix is closed, firm and tucked into the back of your vagina. This means that you can have contractions without the cervix opening. In order for the cervix to respond to contractions it needs to make a number of complex physiological changes (Coad 2011). Relaxin and oestrogen initiate these structural changes, and prostaglandin, leucocytes, macrophages, hyaluronic acid and glycoaminoglycans are all involved in softening the cervix ready for labour. You don’t need to remember all of this scientific stuff (I never can). All you need to know is that it is a complex process, and prostaglandins are only one piece of the puzzle.
Some practitioners offer a membrane sweep during pregnancy to avoid a ‘post-dates’ pregnancy. The procedure involves a vaginal examination where the practitioner places a finger into the opening of the cervix and ‘sweeps’ it around the inside of the lower part of the uterus. The aim is to separate the membranes of the amniotic sac from the lower uterus – this releases prostaglandins. However, a Cochrane Review does not support this practice.
When you are being induced your cervix will be assessed by vaginal examination. If your cervix has already changed and is soft and open enough to get an amnihook in you can skip straight to step 2. If your cervix is still firm and closed, attempts will be made to change it so that step 2 is possible. This is usually done by putting artificial prostaglandins (prostin E2 or cervidil) on the cervix in the form of a gel, pessary or sticky tape. Artificial prostaglandins can cause hyperstimulation of the uterus resulting in fetal distress, therefore your baby’s heart rate will be monitored by a CTG after the prostaglandin is administered. You may also experience ‘prostin pains’ which are sharp strong pains sometimes accompanied by contractions. If there are concerns about giving you prostaglandin (eg. previous c-section) your obstetrician may suggest ways of trying to get your own cervix to release natural prostaglandin by ‘irritating it’ (this is the theory behind membrane sweeps). This is done by inserting a catheter into the cervix and filling it with water ie. you basically have a water balloon sitting in your cervix – very irritating.
Successfully completing step 1 may take a few attempts with re-insertion of prostaglandins. This can take hours or days because you must wait hours before re-assessment and re-insertion. You may respond to the prostaglandin by going into labour therefore skipping the following steps. However, you are still having an induced labour and will usually be treated as ‘high risk’.
Step 2: Breaking the Waters
I realise that this step is not always part of US inductions but I have never experienced this approach, so will stick to what I know… Once your cervix has softened and is open enough to get an amnihook in, your waters will be broken. This is allows induced contractions to be more effective; the baby’s head to press harder on the cervix; and may trigger contractions avoiding step 3. I was also taught that it reduces the risk of an amniotic embolism (amniotic fluid getting into the blood system) but there is no good research supporting this. There are risks associated with artificially breaking the waters. Once your waters have been broken you can wait a few hours to see if labour starts, or go straight to step 3.
Step 3: Making Contractions
You now have a cervix ready to respond to contractions and no amniotic water in the way – next you need contractions. In a natural physiological labour oxytocin is released from the brain and enters the blood stream – it has two main functions:
- It works on the uterus to regulate contractions
- It works in the brain to contribute to the altered state of consciousness associated with labour and promotes bonding feelings and behaviour
In an induced labour, artificial oxytocin (pitocin/syntocinon) is given via a cannula directly into the blood stream. It is unable to cross the blood brain barrier therefore only works on the uterus to regulate contractions. I have written about the risks associated with artificial oxytocin here along with references. Basically, it can be pretty nasty stuff which is why your baby will be monitored closely using a CTG. Women usually describe artificially stimulated contractions as being different and more painful than natural contractions. Having supported women during inductions I am also convinced there is more pain associated with induced contractions. Obstetricians will argue that the physiology of a contraction remains the same whether it is initiated by natural or artificial oxytocin – which is true (see this post for an explanation of how contractions work). However, during an induced labour contraction pattern and intensity increases quickly compared to most natural labours. Women are not able to slowly build up their natural endorphins and oxytocin to reduce their perception of pain. In addition the circumstances and environment that often surrounds induction (intervention, equipment, etc.) can result in anxiety, increasing the perception of pain.
Once your baby is born you will need to continue using artificial oxytocin to deliver the placenta. A physiological placental birth is not safe because you are not producing your own natural oxytocin at the level required. Basically medicine has taken over and must finish the job.
Inducing labour involves making your body/baby do something it is not yet ready to do. Before agreeing to be induced, be prepared for the entire package ie. all the steps. You may be lucky enough to skip one step, but once you start the induction process you are committed to doing whatever it takes to get the baby out… because by agreeing to induce you are saying that you or your baby are in danger if the pregnancy continues. An induced labour is not a physiological labour and you and your baby will be treated as ‘high risk’ – because you are.
More information / Resources
Parent Information Sheet (QCMB)
Ten things I wish every woman knew about induction of labour (Sara Wickham)