What we need to know about labour induction

In one of our latest medical articles here, highly renowned consultant obstetrician, Ms Laura Fulwell-Smith, discusses labour induction in expert detail. 

What is labour induction?

Induction of labour (IOL) is using artificial methods to start labour. It typically involves a number of days being admitted to the hospital with monitoring of both the mum and baby/babies, and there are many different ways it can be undertaken. 

Why might labour need to be induced?

NHS Trusts follow evidence-based guidance released by national bodies such as NICE (National Institute for Health and Clinical Excellence), NHS England (Saving Babies Lives version 3) and the Royal College of Obstetricians and Gynaecologists (RCOG). There are a multitude of reasons but they can include being "overdue" (postdates), diabetes, high blood pressure and pre-eclampsia, or concerns about the health of your baby were they to stay in the womb. Women can also request elective induction. I have booked it for patients when asked with regards to their mental health, concerns about stillbirth, or chronic pain.

What are the common medical reasons for inducing labor?

The most common reasons I see in practice are being post-dates and gestational diabetes. We know that placental function begins to deteriorate slowly after 38 weeks, and substantially after 40+14. Therefore, NICE guidelines suggest we offer IOL after seven days overdue, to allow time for the process to succeed. This placental deterioration happens earlier in some pregnancies - including diabetes. If the diabetes is diet-controlled, babies are normally one week overdue. If medical treatment with metformin tablets or insulin is needed, then the recommendation is to offer IOL at 38 weeks. 

A significant proportion of my work is managing foetal growth restriction - where the baby doesn't meet its growth potential due to the placenta not working as well as it could. This is nobody's fault - it's like asking your kidneys or your liver to work better, you can't change it.

Ideally, we keep all the babies in until 39 weeks as there is ongoing lung and higher brain development right up until this time; but in some situations, there will be concerns that the oxygen levels the baby is getting in the womb are dangerously low, and that we would be able to provide better care for baby if they were to be born. These decisions are complex and individualised, and should be discussed with a specialist consultant obstetrician.

What are the risks associated with inducing labour?

Unfortunately, IOL is not a simple process, especially if it is your first baby. The main risks are that it requires prolonged hospital admission which can lead to feelings of frustration, exhaustion, and even anger. It may not succeed at the first attempt, and your Obstetric team may recommend a 24-hour rest and restart. It involves multiple vaginal examinations which can feel invasive.

Induction of labour is reported to be more painful than spontaneous labour - this means that more women will ask for epidural anaesthesia. This makes it harder to feel what you're doing when you're pushing and an increased chance of needing assistance with the last bit in the form of forceps or ventouse birth. Induction of labour after 39 weeks does not increase the risk of caesarean section - this "cascade of intervention" theory has been debunked in the last few years. 

What are the different methods used to induce labour?

The exact method used to induce labour will depend on your personal clinical circumstances and the policies of your local hospital trust. In general, it is a two- stage process - first ripen and open the cervix to expose the bag of membranes around the baby. This can be done with hormone tablets or gels vaginally, Dilapan rods or a balloon method.

The next step is to break the waters around the babies head - this is done through vaginal examination and the use of a small plastic Amnihook (we call this ARM - Artifical Rupture of Membranes). For some birthing people this will be enough to kickstart labour, but often women will need to commence on "the hormone drip". This is Syntocinon or Oxytocin - the body's "happy" hormone.

Different people respond to this in different ways - some people need a little dose and some need a lot. The dose is slowly increased every 30 minutes until contractions are around three or four in 10 minutes, and then vaginal examinations are conducted periodically to check mother and baby continue to be well. Oxytocin simply brings forward the birth - it does not change the outcome.

How do mechanical methods like a Foley catheter work?

In my NHS trust we use a "Cooks Ripening Balloon" for the first stage of the induction. This is a narrow flexible silicone tube inserted vaginally into the cervix just into the womb. It has two balloons - one for inside the womb and one for the outside (in the vagina). These are then inflated with salty water ("normal saline").

The idea behind the balloon is it stimulates the cervix and uterus to produce hormones to encourage cervical ripening and opening. It is removed after 12 hours, or earlier if your waters break on their own.

If you wish to consult with Ms Laura Fulwell-Smith today, just head on over to her Top Doctors profile.