Why Labour Might Need To Be Induced
Options for starting labour and induction of labour
Preparing for your induction
Before your induction: Membrane sweep
Before inducing labour, you’ll be offered a membrane sweep (1), to increase chances of going into spontaneous labour. To perform this, your midwife or doctor will perform a vaginal examination by inserting their finger through the neck of your womb (cervix) and using circular movements, separate the membranes of the amniotic sac surrounding your baby from the neck of your womb (cervix), which releases hormones (prostaglandins), which help to start your labour.
Some women find the procedure uncomfortable or painful. You may get some cramping and mild vaginal bleeding afterwards. A membrane sweep can be usually offered to you after 39+0 weeks. If labour does not start after your first membrane sweep, you may be offered an additional sweep.
Methods of induction of labour:
Induction of labour is designed to induce the onset of labour by softening and maturing the neck of your womb (cervix) and stimulate contractions. 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 using a vaginal examination and calculating a Bishop score)
Whether your waters have broken
Your preferences.
What is Bishop score?
The Bishop score (1) is a number obtained by doing a vaginal examination, and is based on:
How many cm dilated you are – dilatation is from closed – 10cm.
Length (effacement) of the neck of your womb (cervix) – effacement is long (0%) – paper thin (>80%)
Position of the neck of your womb (cervix) in your vagina – position goes from posterior to anterior during labour.
Consistency of the neck of your womb (cervix) – consistency goes from firm to soft during labour.
How far down the pelvis your baby’s head is (station) – station starts at -3 (high) to +2 (at the vaginal entrance).
When your Bishop score is 6 or less you will be offered:
Medication to ripen the neck of your womb (cervix).
Mechanical method (a balloon inserted into the neck of your womb).
When your Bishop score is more than 6, you will be offered:
Breaking your waters (amniotomy) and giving a hormone (oxytocin) drip through a vein in your arm.
Methods of induction of labour
Medication for induction:
There are various medications available to induce your labour.
The medication used for induction is called prostaglandin.
There are several different types of prostaglandins that can induce labour. They are usually given vaginally but may sometimes be given to you by mouth (orally). Prostaglandins usually take 12-24 hours to ripen the neck of your womb (cervix). This depends on the type of prostaglandin, its dose and how ready the neck of your womb (cervix) is. Talk to your team about which prostaglandin they use in your hospital. (1, 2,3)
Mechanical methods of Induction of labour:
Mechanical methods for induction stretch the neck of your womb (cervix) promoting hormone release. This can be done by using either a balloon catheter or osmotic dilators.
A balloon catheter is inserted into the canal in your cervix to reach the space inside the womb just outside the amniotic sac covering your baby and inflated with water to hold it in place, after which the cervix gradually dilates and releases hormones which can induce the onset of labour. (4)
An osmotic dilator is a medical device used to dilate the cervix by swelling as it absorbs fluid from the surrounding tissue in your body (1)
Mechanical methods of induction of labour usually work within 24 hours. Talk to your team about how long it will stay in for. (5)
Mechanical methods of induction of labour are safe for you and your baby and they are as effective as vaginal medication at inducing labour. (5)
Induction with a mechanical device in the neck of your womb is less likely to cause excessive contractions than vaginal medication. It is recommended to opt for this method of induction if you have had a previous caesarean birth. Talk to your team about the option that is best for you and your circumstances.
Prostaglandin Pessary
Prostaglandin Gel
Balloon Dilator
Breaking of the waters (amniotomy) and the hormone drip (oxytocin):
When your cervix is examined and it is deemed appropriate to break your waters (artificial rupture of membranes/amniotomy), this will be undertaken on the delivery suite. 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. Any delay may lengthen your labour and may increase the chance of your baby developing an infection.
Breaking 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 spontaneously. It is also performed during spontaneous labour if progress slows down. It may increase the strength and number of contractions you have therefore shortening labour by about an hour. It does not involve giving any medication, the process involves the puncturing of the membranes with a crochet‐like long‐handled hook during a vaginal examination.
Breaking your waters (amniotomy/artificial rupture of membranes)
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. (6,7)
Hormone drip (Oxytocin)
A hormone medication called oxytocin can be used to increase the amount and strength of your contractions. We would need to monitor your baby’s heart rate and your contractions continuously while its given using CTG (cardiotocography). Using the hormone drip may shorten the length of your labour. It does not affect your mode of birth or your baby’s condition. (1,7)
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). The senior members of the team will need to review you and may reduce or stop the hormone drip (oxytocin), if your contractions continue despite this, we can give you medication (tocolytic) to resolve this. These measures will give your baby more time to recover between contractions by slowing them down and making them more regular and effective. (1, 7, 8)
If labour does not start despite being induced, a doctor will discuss with you what your options are going forward. They will review your pregnancy notes and the baby’s latest heart rate (CTG) trace. Depending on your specific case they may offer you:
Further attempt at inducing labour – this may include trying to induce you using a different method than was originally used.
A period of rest after which we will re-examine the neck of your womb (cervix) to see if there has been any change.
Awaiting events i.e. seeing if you go into active labour on your own.
A Caesarean birth.
Almost 1 in 3 women in the UK will have their labour induced. Although over half result in active labour and a vaginal delivery, for some women this is not the case.
We do not always know why active labour may not happen for you following induction, however we put you and your baby at the centre of our care and you making an informed decision about your care is most important to your team.
References:
National Institute for Health and Care Excellence: Inducing labour [NG207] [Internet]. NICE, London; 2021 [cited 2024 Aug 14]. Available from: https://www.nice.org.uk/guidance/ng207
Hofmeyr GJ, Gülmezoglu AM, Pileggi C. Vaginal misoprostol for cervical ripening and induction of labour. Cochrane Database of Systematic Reviews 2010, Issue 10. Art. No.: CD000941. DOI: 10.1002/14651858.CD000941.pub2
Kerr RS, Kumar N, Williams MJ, Cuthbert A, Aflaifel N, Haas DM, Weeks AD. Low‐dose oral misoprostol for induction of labour. Cochrane Database of Systematic Reviews 2021, Issue 6. Art. No.: CD014484. DOI: 10.1002/14651858.CD014484
Rattanakanokchai S, Gallos ID, Kietpeerakool C, Eamudomkarn N, Alfirevic Z, Oladapo OT, et al. Methods of induction of labour: a network meta-analysis. Cochrane Pregnancy and Childbirth Group, editor. Cochrane Database Syst Rev [Internet]. 2023 Jan 3 [cited 2024 Aug 15];2023(1). Available from: http://doi.wiley.com/10.1002/14651858.CD015234
De Vaan MD, Ten Eikelder ML, Jozwiak M, Palmer KR, Davies-Tuck M, Bloemenkamp KW, et al. Mechanical methods for induction of labour. Cochrane Pregnancy and Childbirth Group, editor. Cochrane Database Syst Rev [Internet]. 2023 Mar 30 [cited 2024 Aug 15];2023(7). Available from: http://doi.wiley.com/10.1002/14651858.CD001233.pub4
Recommendations: Intrapartum care: Guidance 1.8.40 to 1.8.42. NICE. Available at: https://www.nice.org.uk/guidance/ng207/chapter/recommendations
Smyth RMD, Markham C, Dowswell T. Amniotomy for shortening spontaneous labour. Cochrane Database of Systematic Reviews 2013, Issue 6. Art. No.: CD006167. DOI: 10.1002/14651858.CD006167.pub4
Leathersich SJ, Vogel JP, Tran TS, Hofmeyr GJ. Acute tocolysis for uterine tachysystole or suspected fetal distress. Cochrane Database of Systematic Reviews 2018, Issue 7. Art. No.: CD009770. DOI: 10.1002/14651858.CD009770.pub2
