Here's what you need to know about being induced

Are you desperate to get that baby out, no matter what it takes? Dr Anil Sharma explains what it means to have labour induced. 

While the majority of pregnant women will go into labour spontaneously, around one to two in 10 women need a bit of help. Most pregnancies last for around 40 weeks, but some will go overdue, or perhaps there will be another medical issue that means induction is necessary. While some pregnancies are induced for social reasons or by maternal request, induction of labour involves an interventional process and by and large it should be undertaken for valid reasons. In other words, when induction is undertaken, ideally it should be because carrying on with pregnancy involves greater risk to the mum-to-be or baby (or both) than the process of induction. Having had a previous Caesarean section does not mean that induction is not possible, but the pros and cons need careful consideration, as the risks of uterine scar rupture in labour are slightly higher than with natural labour.

This article is a general guide to induction of labour. Detailed assessment and discussion with your own lead maternity caregiver (LMC) is advised.

During pregnancy, but especially towards the end (by around 38 weeks), your LMC should have discussed labour, induction, and other types of deliveries with you. This will involve information about the risks associated with pregnancies that last longer than 42 weeks, and their options.

Reasons for induction

The most common reason is due to your pregnancy going "post-dates", which usually means going beyond 41 weeks and 4 days pregnant. Other reasons include medical problems of pregnancy, including pre-eclampsia (a syndrome that usually involves blood pressure), slow growth in the baby, or unexplained pain or bleeding at term.

How an induction happens

Once the decision to undertake an induction of labour is made, the biggest physical hurdle is overcoming the resistance to birth by the cervix. After all, the normal cervix is thick, long, and closed, and has helped keep the baby inside the uterus.

Normally, the cervix gradually softens, shortens, and starts to dilate as the pregnancy gets ready to end and labour is just around the corner. Some chemicals called prostaglandins are released naturally to help these changes occur.

 If the cervix is still "unfavourable" for labour, a prostaglandin (Prostin) gel is inserted into the upper vagina. This gradually helps bringing about the changes noted above. This aim of changing the cervix can take around four doses of Prostin, and this is done gradually over two days or thereabouts. A number of  tests are undertaken during this time to make sure the baby (and mum-to-be) don't have any side effects due to the Prostin.

Once the cervix is significantly changed, the bag of waters (the membranes) can be broken (this is called amniotomy). The Prostin may work quicker, needing less than four doses, but occasionally more than this is needed. While this whole process can be long and arduous (not least because the whole family is very excited about the arrival!), it pays to remember that the natural means of getting the cervix ready usually takes weeks, not days.

The induction process takes place in hospital under careful conditions. If and when you need pain relief, this is organised just as it is for natural labour.

Oxytocin is secreted by part of the brain into the bloodstream, and causes the actual contractions of labour to occur. Syntocinon is the laboratory-made version of oxytocin, and is used to start the uterus contracting (once the waters have been broken). It is given by a drip into a vein, but this also means that it can be increased or decreased, or even stopped if necessary.

Amniotomy (breaking the waters)

This process is usually not as painful as it sounds. It is undertaken with a small hook (like a crochet hook) during an internal examination. After the waters are broken, it is usual to start syntocinon to get contractions started. Sometimes, however, especially if you have had a baby already, your obstetrician  or midwife may suggest you get up and about (mobilise) for a few hours to see if you start contracting on your own.

Pain relief during induction

While it is a commonly held belief that induction is more painful than natural labour, this is not proven. What is, however, logical is that the process of going from not-in-labour to labour is faster with induction than natural labour. It is therefore no surprise that the pain that is associated with this is greater than a gradual onset of pain over days. 

All the usual methods of pain relief in labour, including epidurals, are fine in induced labour, but epidurals are best reserved for when you are actually in labour (more than 3cm dilated).

Membrane sweeps and other induction methods

This involves an internal examination, and a gloved index finger is then passed into the cervical canal to stretch and sweep the area where the membranes are in approximation to the upper part of the cervix. This has the effect of releasing the natural prostaglandins as discussed above.

Membrane sweeping makes spontaneous labour more likely, and reduces the need for formal induction of labour to prevent prolonged pregnancy.

 Discomfort and slight vaginal bleeding are possible from the procedure, but usually well-tolerated by the mum-to-be. Membrane sweeps are commonly used in the UK, and their advantages are becoming more apparent in New Zealand.

Despite widely held beliefs about acupuncture, homeopathy, herbal supplements, castor oil, hot baths, enemas, sexual intercourse, or eating hot curries, there is unfortunately no actual good evidence to support their use as agents for the induction of labour. Try any or all of the above if you want to, but don't be surprised if you end up in the bathroom with a tummyache.

If induction doesn't work…

If induction does not work, again it becomes an issue of weighing up the pros and cons of the options specifically for you and your pregnancy circumstances. It may be that further use of Prostin is thought to be reasonable, but the only other option is delivery by Caesarean section.

Women who do not wish to have an induction when offered will need to raise their concerns with their LMC. In the case of declined induction for post-dates pregnancy, the risks will need to be discussed and if you accept the small risk of serious outcome, then the pregnancy can continue. However, it would be advised that frequent foetal heart rate monitoring and ultrasound scans to check for foetal wellbeing should be undertaken.

Induction of labour is a necessary intervention, as nature sadly doesn't have all the answers. It also involves small risks to fetal wellbeing, and risks of other intervention such as Caesarean section.

Because induction does involve significant interference and other risks, ideally it should only be carried out if the risks of leaving the pregnancy to proceed are greater than the risks of induction. However, when used in appropriate circumstances, induction of labour is a well-tolerated and accepted means of achieving safe vaginal delivery.

Dr Anil Sharma is a specialist doctor in gynaecology and maternity. He is very involved in lectures and updates for family doctors and frequently takes part in debate regarding women's health and maternity for print media and radio. He believes that anxiety and fear can be conquered by knowledge. Anil tries hard to be a hands-on and fun father (putting golf and cars on hold for the time being) to their three daughters, who were all born here. Anil has his own website, www.dranilsharma.co.nz, which has further details about his practice.