Why an induction of labour may be offered or advised

Options for starting labour and induction of labour

There are different ways of starting labour depending on the readiness of your cervix, your pregnancy history and what is available at your hospital.

Before your induction

Membrane sweep:

A membrane sweep can increase your chance of going into spontaneous labour. It involves your midwife or doctor performing a vaginal examination by inserting their finger through the cervix and using circular movements, to separate the membranes of the amniotic sac surrounding your baby from the cervix. This releases hormones (prostaglandins), which help to start your labour. The procedure is usually uncomfortable or can be painful. You may get some cramping and mild vaginal bleeding afterwards. A membrane sweep is usually offered to you after 39+0 weeks but can be offered earlier. If labour does not start after your first membrane sweep, you may be offered an additional sweep.

Methods of inducing labour

Induction of labour is designed to induce the onset of labour by softening and dilating the cervix and stimulating contractions like active labour.

There are a variety of methods available for inducing labour, both medical treatments and mechanical methods. 

The choice of the method depends on: 

  • The readiness of your cervix (assessed by vaginal examination). 

  • Whether your waters have broken 

  • What is available at your unit

  • Your preferences.


Different methods for induction of labour

Medications:

There are different medications to help induce labour. They are normally given vaginally but can also be given by mouth. The method used may vary from hospital to hospital. Medications are usually prostaglandins – these are similar to the natural prostaglandins released to ripen the cervix. They usually take 12-24 hours to help get your cervix ready for labour. 

Mechanical methods:

Mechanical methods stretch the cervix and encourage your body to produce natural prostaglandins to help start labour. There are different methods. A balloon catheter or osmotic dilator are common methods. 

A balloon catheter is a small thin plastic tube that is inserted into the vaginal canal and into the cervix. It sits just outside your baby’s amniotic sac. There is a small balloon at the end of this flexible tube, and this gets inflated with water. This encourages the cervix to dilate and release hormones to help get labour started.

An osmotic dilator is a device used to dilate the cervix by getting it to swell as it absorbs the fluid from the tissues close by in your body.

These mechanical methods normally work within 12-24 hours, but this can vary from person to person.

Induction with a mechanical device is less likely to cause excessive contractions compared with vaginal medication. 

Prostaglandin pessary

 

Prostaglandin gel

 

Balloon dilator

 


Breaking of your waters (amniotomy):

 Breaking of the waters (artificial rupture of the amniotic membranes or amniotomy) is part of the induction process if your waters haven’t broken on their own. It is also performed during spontaneous labour if progress slows down. It may increase the strength and number of contractions you have. It does not involve giving any medication, the process involves the puncturing of the membranes with a little plastic hook during a vaginal examination. This usually happens on the labour ward/delivery suite. 

After breaking your waters, your contractions may speed-up and you may experience more pain. 

Once your waters are broken, if your progress in labour is slower this may increase the chances of your baby developing an infection. 


The hormone drip (oxytocin): 

After your waters have been broken, you will be offered a hormone drip (oxytocin). You can choose to have this immediately or delay starting to see if you contract regularly after breaking your waters. 

 Delaying this may lengthen your labour and may increase the chance of your baby developing an infection.

Oxytocin can be used to increase the number and strength of your contractions. We do this by slowly increasing the dose of oxytocin through a drip in your hand/arm to aim for 3-4 contractions in 10 minutes (mimicking physiological active labour). 

Cannula with drip attached

 

We need to monitor your baby’s heart rate and your contractions while its given using continuous electronic fetal monitoring (cardiotocography/CTG). This is usually 2 bands around your abdomen to monitor your contractions and your baby’s heart rate. Using the hormone drip may shorten the length of your labour.

 

Oxytocin may cause you to contract too frequently (uterine hyperstimulation), this is more painful for you and may reduce oxygen to your baby temporarily, if this happens for too long your baby may show signs of distress on the heart rate monitor (CTG). Midwives and doctors may reduce or stop the hormone drip (oxytocin). If your contractions continue despite this, we can give you a medication to stop contractions.  Your midwife and doctor will then make a plan with you.