Why an Induction?
Sometimes your doctors may feel that it’s safer not to wait for your labour start and that it needs to be started it for you. Bringing on your labour is usually called ‘induction of labour’ or ‘induced’. At present, an estimated 10% of all labours in large hospitals worldwide are induced (58).
The main aim of induction is to improve health outcomes for you and your baby; however, sometimes, induction is used more frequently than necessary. It is important to know that ultimately the choice for induction is yours. It is your right to be informed, and consent to any procedures when you are fully aware of all of what it means for you and your baby.
Induction of labour can occur for many reasons. However, one common reason is that your due date has passed and there are no signs of imminent labour (‘post-dates’. Post-dates induction usually occurs when you are getting close to two weeks post your expected due date. This timing is of concern as because research has shown that after 42 weeks, the placenta doesn’t work as well, and risk of stillbirth increases (59). However, despite the improvement in outcomes with the induction of labour, the risk to your baby remains minimal (60).
We may also recommend induction under the following circumstances:
- Gestational diabetes or diabetes
- Pre-labour and premature rupture of membranes
- Intra-uterine growth restriction (IUGR)
- Blood pressure problems
- Multiple pregnancies
- Disorders of pregnancy, e.g. pre-eclampsia, cholestasis
- Large for gestational age baby (LGA) or small for gestational age (SGA) this means your baby is a larger or smaller than expected
- Any concern for yours or your baby’s health
- Placental problems
- Uterine infection
Doctors and midwives worldwide follow a general process. Practise will differ with your birthing unit.
Your Bishops Score
Before your induction, we will ask for your permission to conduct a vaginal examination (VE). This exam helps to determine what we call a ‘Bishops Score’. This score suggests which method of induction is the most suitable. During the VE they will evaluate:
- How soft your cervix is
- The length of your cervix
- How dilated your cervix is,
- The position of your cervix, and
- How far down your baby’s head is sitting
Each feature of this examination will be assigned a score, which, when totalled, gives us your Bishop’s score. A score under seven indicates your cervix is probably not ready to labour yet. Women with this score at the start of their induction will usually have their cervix ripened with either a cervical balloon or prostaglandins. Women scoring higher than seven usually progress straight through to having their waters broken.
Your Bishops score will change as your induction progresses. After your labour establishes, your Bishop’s score is no longer relevant. Any VE after this time will be looking for some different signs of progress.
The main induction methods are:
Stretch and sweep (membrane sweep, or strip and stretch)
This procedure is carried out by your midwife or doctor and involves an internal vaginal examination (VE). Your midwife or doctor puts a couple of gloved fingers into your vagina and feels for your cervix as gently as possible. Once they find your cervix (which is usually at the back), they insert their index finger into the opening of your uterus. They then use a circular motion to try to separate the membranes of the amniotic sac, containing the baby, from your cervix. This action releases hormones, called ‘prostaglandins’, which prepare the cervix for birth and assists to initiate labour.
Prostaglandins are hormones which stimulate your cervix to soften and prepare for labour, in some cases stimulating the uterus to contract. More common names are cervical ripening, prostaglandins, or ‘the gel’. We insert these gels behind your cervix; hence, this will involve a vaginal examination. The prostaglandins will soften the cervix and help it to dilate enough for us to break your waters.
Cervical balloon or balloon catheter
This device is a long tube with one or two balloons on the end, which we insert into your cervix and vagina and fill with normal saline. We leave it to stretch the cervix for a prescribed amount of time, and when removed, attempt to break your waters.
Breaking your waters.
To break your waters, your cervix needs to be in an optimal position. It also needs to be open enough for your care provider to break your waters safely. This procedure removes the cushion from around your baby, bringing his head down onto your cervix. This pressure will stimulate your contractions.
The hormone drip contains a synthetic version of the hormone oxytocin (commonly called Pitocin ® – ‘Pit’ or Syntocinon ® – ‘Synto’). We administer this through a cannula inserted into your arm. It travels through your body and stimulates your uterus into contractions. However, it does not cross the blood-brain-barrier, so does not contribute to bonding.
Your induction may include one or all these methods for stimulating your labour. Each of these comes with its own set of risks and benefits. Because of these risks, your baby will require close monitoring throughout this process. However, if we offer induction, it is because the risk of inducing your labour is lower than the risk of your remaining pregnant.
Depending on the facilities available, you may have to remain in one position for monitoring to occur. As such, it may restrict your movement. If your body hasn’t yet begun to prepare for labour on its own, induction can be a lengthy process. Once labour starts, it should proceed normally, but it can sometimes take 24-48 hours to get you into labour. Induction of labour in some research indicates a higher need for further intervention and medically assisted birth.
If induction does not work, your doctor and midwife will assess your condition and your baby’s wellbeing. We may offer you another attempt at induction or a caesarean section. Your midwife and doctor will discuss all the options with you.
To read more about induction of labour, please click here.
Nikki-Lee Rossiter (BMid), Registered Midwife/ Dr Janelle McAlpine (PhD), Clinical Midwife
Photo by Tyler Olson used under license from Shutterstock.com