Induction of labour: what is induction and when to induce?
May is Maternal Mental Health Month, a dedicated time to consider the emotional and mental health challenges mothers face before, during, and after pregnancy.
To mark this, our specialist maternity care team considered the common themes of birth trauma shared by our clients, and it became clear that induction often plays a part in their experiences.
Clients often tell us that they feel they were poorly informed about the induction process and it was not something that was talked about in detail during their pregnancy. With this in mind, our team has prepared a series of articles focusing on induction of labour, the different types of induction, its risks and benefits, and how to empower women to play an active part in the care they receive by asking questions that allow them to weigh up their options.
The rate of induction has increased by over 10% in the last decade and it is now estimated that a third of the births in England are induced. This increase is the result of a variety of factors, including updated NICE guidelines for earlier induction at 41 weeks, maternal health factors such as maternal age, BMI, and more complex pregnancies, but also NHS service pressures.
What is induction of labour?
Induction of labour (or IOL) is a medical intervention to start labour artificially before it begins naturally. The process involves stimulating contractions of the uterus to encourage a vaginal birth.
The assessment of suitability often includes the Bishop Score, which is a clinical tool used to assess how ready the cervix is for labour and how likely induction is to lead to a successful vaginal delivery.
The score looks at five features: cervical dilation, cervical effacement, cervical consistency, cervical position and fetal station. Each component is scored and a higher score will indicate a higher chance of vaginal birth and shorter induction time. This will also help to determine whether induction should proceed immediately and which method of induction is appropriate. Other factors such as the maternal gestational age, medical condition, and baby wellbeing will be considered. The Bishop Score can change due to cervical changes and for this reason should be reassessed throughout the induction process.
Although the terms augmentation and induction are often used interchangeably, they are different in practice. While induction aims to initiate labour before spontaneous onset, using mechanical or pharmacological methods, augmentation is the stimulation of uterine contractions once labour has been initiated spontaneously, but where the progress is inadequate. One of the main issues with augmentation is often the lack of consensus over what is considered ‘adequate progress’ in active labour.
When is induction recommended?
When appropriately used, induction can reduce certain risks of birth significantly. The fundamental principle behind induction is therefore to balance the risks and benefits. Induction of labour is usually recommended when the risks of continuing the pregnancy outweigh the risks of induction for both the baby and the mother.
The most common reasons for an induction are:
- Post-term pregnancy – a pregnancy is considered at term from 37 weeks. Most guidelines recommend offering induction between 41+0 and 42+0 as the risk of stillbirth and neonatal complications increases after this date.
- PROM (premature rupture of membranes) – if the waters break but labour does not start naturally, induction might be recommended to reduce the risk of infection.
- High blood pressure – some maternal conditions causing high blood pressure such as gestational hypertension, eclampsia and pre-eclampsia may necessitate induction as this can lead to restricted growth, low birth weight, and increase the risk of neonatal unit admission for the baby and potential organ damage for the mother.
- Diabetes – gestational and pre-existing diabetes can increase the risk of stillbirth and excessive fetal growth, making baby weight/growth monitoring important and induction advisable in some cases.
- Concerns about the baby’s wellbeing – if there is evidence of poor fetal growth, reduced amniotic fluid (oligohydramnios), abnormal fetal heart rate, or decreased fetal movements, induction may be recommended.
When is induction not recommended?
When a vaginal birth itself is unsafe, induction of labour is not appropriate and there are a number of scenarios where induction may be contraindicated, including placenta praevia (where the placenta covers part or all the cervix), transverse fetal position, umbilical cord prolapse, active genital herpes infection or a history of previous caesarean sections. In these situations, alternative methods of delivery such as caesarean section should be considered.
In other circumstances, individualised decision making will be required and induction should be carefully considered or avoided if, for example, the cervix is extremely unfavourable, the gestational age is uncertain, or there are significant maternal health concerns.
Shared decision-making
Respecting patient autonomy should always be paramount to decision making and induction should not occur if the woman declines induction after being appropriately and fully informed. The mother should be given clear information as to why the induction is being offered, the alternatives (including expectant management and caesarean section), their individual circumstances, and potential risks and benefits.
Conclusion
Induction of labour is a valuable and often life-saving intervention when used appropriately, but it is not a routine intervention recommended for every pregnancy, and it is important for expectant mothers to understand when induction is advised and when it is not, in order to help them make informed, confident choices about their birth experience.
The next article in this series will explore the different types of inductions and the risks and benefits of these. In the meantime, if you have experienced issues in relation to induction of labour and would like to discuss this further with us, please do not hesitate to contact our specialist maternal care team.