WHAT IS INDUCTION OF LABOUR?
Induction of labour is the process of using drugs or other methods to encourage labour to start artificially rather than waiting for labour to start naturally. You will be offered an induction of labour if your doctor thinks that it is safer for your baby to be born sooner rather than continuing with your pregnancy (NCCWCH 2008a). Induction can be a lengthy process.
This information will explain what to expect, the risks and benefits of an induction and will help you make an informed choice.
Ask your doctor:
- Why has an induction been recommended?
- What are the potential risks with continuing your pregnancy until labour starts naturally?
- What are the potential risks with having an induction of labour?
- What are the procedures and care that are involved with an induction?
WHY HAS AN INDUCTION BEEN RECOMMENDED FOR ME?
Induction of labour has been offered because continuing with the pregnancy may cause risks to you or your baby’s health. These are some of the common reasons when induction may be offered to you:
- Your pregnancy is prolonged (over 41 weeks);
- Your membranes have ruptured but labour has not begun;
- You have diabetes in pregnancy;
- Your baby is small and/or growing slowly;
- You have a condition which threatens the health of you or your baby (e.g. high blood pressure, kidney disease);
- There are concerns about your baby (low fluid around the baby, less foetal movements).
WHAT TO EXPECT?
Induction of labour is usually planned in advance. You will be able to discuss the advantages and disadvantages with your midwife and your doctor.
The process of induction can be different for everyone; most women will have their babies within 24 hours, for others induction may take up to two to three days. The success of labour induction in leading to a vaginal delivery depends on many factors, one of which is how far your cervix is dilated and shortened. The more dilated and the more shortened your cervix, the more likely you are to deliver vaginally. Sometimes, after your membranes have ruptures, contractions may not start and labour does not become established. In this situation, your doctor will recommend a caesarean section.
Induction is usually done in the hospital, in the Delivery Suite. This will allow your doctor to monitor your baby prior to the start of the induction to make sure the baby is doing well.
Depending on why your doctor is inducing labour, you may already be in the hospital. Your doctor may do an ultrasound to determine how your baby is doing as well as location of the placenta and foetal weight. Your doctor will also determine how far along you are in your pregnancy. After this is done, an intravenous line may be placed for medicine to be given. Your baby may be put on a foetal monitor to record the heart rate and the frequency of uterine contractions.
Your doctor will do an exam of your cervix to determine how dilated it is. Your nurse will take your temperature, heart rate, and blood pressure to make sure that you are doing well.
Before you go into labour, you may want to consider what pain relief you may want if the induction works and makes your contractions very strong and difficult to cope with.
Once you have reached your due date, you may be offered a membrane sweep at around 40 weeks, followed by another at 41 weeks. This procedure has been shown to increase the chances of labour starting naturally within 48 hours of the procedure and can reduce the need for other methods of induction of labour.
You may also be offered a membrane sweep if induction of labour is being done for medical reasons. The timing will be advised by the doctor responsible for your care. If your waters have broken but labour has not started, membrane sweeps are not recommended, as they can increase your risk of infection.
A membrane sweep involves the doctor or midwife putting two fingers inside your cervix and making a circular sweeping movement to separate the membranes from the cervix. This increases the production of hormones called prostaglandins which can encourage labour to start.
There may be some discomfort or bleeding but it will not cause any harm to you or your baby. If you decide against a membrane sweep, you can wait for labour to start naturally or use a more formal method of induction as explained below.
If labour does not start after a membrane sweep, you will be offered induction of labour.
WHAT TYPE OF INDUCTION AM I LIKELY TO HAVE?
There are several ways to induce labour. To determine the best method of induction for you, your doctor or midwife will do a vaginal examination to check how ready your cervix is. Based on this examination, they will recommend one of the following methods of induction:
- A hormone called prostaglandin
- Balloon catheter
- Artificial rupture of membranes
- A hormone called oxytocin.
The process of induction will vary for everyone. It may require one of a combination of these methods.
METHODS OF INDUCTION
Prostaglandin is a naturally occurring hormone that prepares your body for labour. A synthetic version has been developed to mimic your body’s natural hormone. This hormone is placed in your vagina either as a gel, a tablet or a pessary (like a tampon) that works to ripen (soften) your cervix.
Once the prostaglandin has been inserted, your baby will be monitored and you will need to stay in the hospital.
Prostaglandins are not suitable for all women, for example if you have had a previous caesarean section or a reaction to prostaglandins in the past. Your doctor may therefore recommend a balloon catheter to ripen your cervix.
This catheter is a thin tube which is placed inside your cervix and a small balloon inflated to place pressure on your cervix. This pressure should soften and open your cervix. This catheter will stay in place for several hours until either it falls (indicating that your cervix has opened) or until you are re-examined.
Other mechanical methods involve dilators that swell as they absorb cervical and other fluids, putting pressure on your cervix and encouraging it to open. (Ezakoff and Kilpatrick 2013, Jozwiak et al 2012)
If your labour does not start using these methods, your doctor may recommend that you move on to other methods of induction (NICE 2015a).
Artificial rupture of membranes (“breaking your waters”)
If your waters have not broken, artificial rupture of membranes may be recommended. It can only be done when the cervix is soft, partially dilated (open) and in a good position.
During a vaginal examination your doctor or midwife puts a small hole in the bag of membranes or waters around your baby. This is done with a small instrument during a vaginal examination and can only occur once your cervix is open.
Once your membranes have ruptures, contractions may start naturally, if not an oxytocin infusion (Oxytocin®) will be started.
Oxytocin® is a synthetic hormone that mimics your body’s natural hormone called oxytocin. It is given through an intravenous infusion in your arm and stimulates contractions of the uterus. The infusion is slowly increased until you are having strong regular contractions. The infusion will continue until after your baby is born.
Once oxytocin has started your baby’s heart rate will be monitored throughout labour using a cardiotocograph (CTG) machine.
The contractions brought on by oxytocin tend to be more intense than natural ones. So you should be offered an epidural for pain relief (NCCWCH 2008a).
WHAT RISKS ARE INVOLVED WITH AN INDUCTION OF LABOUR?
The induction may not work
Occasionally, the process to ripen the cervix does not work, which means your cervix has not opened enough for the membranes to be ruptures. If this happens, your doctor will talk about your options. These may include returning home until a later date, using a different method of induction, or you may require a caesarean section.
Over-stimulation of the uterus
One of the side-effects of the synthetic hormones is they may cause the uterus to contract too much. This can sometimes cause stress to you and your baby. If this occurs you may be given medicine to relax the uterus. If you have a hormone pessary it will be removed.