What you need to know about inducing labour

Why induction might be offered

All women who haven't spontaneously gone into labour by 42 weeks of pregnancy will be offered induction. Besides the fact you're likely to be fairly fed up by that stage, there's also an increased risk of stillbirth or other complications for the baby which increases the longer past your due date you are.

"The main reason pregnancy after 42 weeks can be problematic is that it's a bit more common that the placenta starts to run down, and may not give the baby as much food and oxygen as it needs," explains Dr Pat O'Brien, a consultant obstetrician and spokesperson for the Royal College of Obstetricians and Gynaecologists (RCOG). "Nothing changes dramatically the minute you hit 42 weeks; it just becomes significantly more common after that stage. And of course the baby is also getting bigger and bigger," he adds.

Other reasons why induction might be offered include if your waters break early - more than 24 hours before labour starts - or if there are health concerns about either the mother or the baby.

"There is a long list of reasons in the mother and reasons in the baby for why you might want the pregnancy to come to an end: if a baby is getting very big, or the opposite, if it's not growing very well; if the mother has high blood pressure, which in pregnancy can lead to pre-eclampsia; or if the mother has diabetes," O'Brien says.

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Do you have to be induced?

Whether or not to be induced is your choice. If you prefer not to accept the offer of induction, you can keep waiting, under close monitoring, for labour to start naturally. However, it's also important to be fully aware that there are clear risks associated with waiting.

According to NICE guidelines, your doctor or midwife should allow you time to discuss the information with your partner before coming to a decision; encourage you to look at a variety of sources of information; invite you to ask questions, and encourage you to think about your options; and support you in whatever decision you make.

The most important thing is that you're able to give informed consent, says Kate Marsh, midwifery manager at charity Tommy's. "You should have a conversation - probably with your midwife, if it's a low-risk post-date induction - about any considerations, the reasons for induction, and if you're happy to go ahead," she says. "It's easy to feel railroaded sometimes by guidelines or hospital policy, but you do have a choice in the matter."

How induction works

Before labour is induced you'll be offered a cervical sweep, or membrane sweep. With this option, a midwife or doctor will sweep their finger around your cervix, hopefully causing the membranes of the amniotic sac around your baby to separate from your cervix, and releasing hormones called prostaglandins, which may trigger labour.

A membrane sweep might cause discomfort or bleeding afterwards, but shouldn't be painful. If this doesn't work, you'll next be offered induction, which O'Brien says can be thought of as three possible stages:

1. A hormone gel or tablet (pessary) is applied or inserted vaginally

The hormones used are called prostaglandins, and are very similar to your own prostaglandin, which is released as you go into labour naturally.

"You might feel some period-type pains, you might get some contractions, or you might feel nothing. During this time you can go for a walk, get a coffee or whatever," O'Brien says. "Usually by around lunchtime [having started induction in the morning] you'll have some more of the hormone and at that point, hopefully, the labour starts - in other words, contractions start coming regularly."

2. Your waters are broken

If this first stage alone doesn't start labour, but the cervix has begun to dilate, the next step involves breaking the waters.

"The water is like a balloon of water around the baby, so the midwife can use a plastic hook to break that balloon. Over the next couple of hours, as the water comes out, that can trigger some of the woman's own natural hormones, and the contractions start again," O'Brien explains.

3. Oxytocin is given through a drip

Finally, he says, the third stage of induction uses the hormone oxytocin, which is administered through a drip in the woman's arm.

"We start off with a very low level, increasing in little steps every 15 minutes, until the contractions are coming every three minutes or so, which is what you would expect in normal labour," O'Brien says.

Some women will need just the gel, some will need the gel and the waters breaking, and some will need all three. If none of these work, your doctor will discuss all the options with you, which may include another induction or a caesarean section.

Misconceptions about induction

It's common for women to be concerned about induction, which in the past was believed to increase the risk of labour complications. However, O'Brien explains, obstetricians no longer believe this is the case.

"We used to think inducing labour increased your chances of caesarean section. It's true that if you take 1,000 women who've had induced labour, and 1,000 women whose labour started by itself, the rate of caesarean section is higher in the induction of labour women. So that's where that advice and guidance came from for years. But then people started to do better studies, [which recognised that] women who have their labour induced are not the same as women going into labour naturally," he explains.

"If you look at the women who have their labour induced, some are induced because they have very high blood pressure, some because the baby's getting very big, etc. So we're not comparing like with like," O'Brien adds. "In many of these cases, the reason why a woman who had induction then had to have a caesarean section was because the baby was too big, or her blood pressure got even worse."

In other words, he explains, it's the circumstances surrounding the birth that increase the risk, rather than the induction process itself. So, if you're induced at 42 weeks because the baby is getting too big, the labour is no more likely to be painful or complicated as a result of induction than if you were to go into labour spontaneously at the same stage. One thing he says women should be aware of, however, is that induction can be a slow and frustrating process.

"Once the labour gets started, it will be much the same as if the labour had started by itself. The bit you can't predict is how long it's going to take from when you have your first lot of hormone gel until the time labour gets going," he explains. "If you're very lucky, it could be a few hours after the first lot of gel. If you're unlucky, you could be sitting there 24 hours later, after three lots of gel, and still not in labour."

How to prepare

Despite the unpredictable nature of induction, there are things you can do to prepare and ease your mind. "Be prepared for a lot of waiting around, and think about what generally helps you relax. Some people like to read, listen to music, go for a walk, so just think about what's going to help you in that process," Marsh suggests.

Likewise, she says: "Make sure you understand exactly what's involved and what your options are, because it may vary slightly in different maternity units. If you're really nervous and anxious, and finding it difficult to relax, that can sometimes make the pain worse and hinder things, so think about your environment and what you can do to help. Even simple things like bringing in your own pillow, with its smell of home, can help."

Natural induction

Of course, if you are edging closer to the 42-week mark, you've probably heard all the old wives' tales in the book about how to bring on labour naturally - from curry to raspberry leaf tea, and even having sex. Sadly though, there's not a great deal of evidence they work.

"There is a little bit of evidence about raspberry leaf tea, but you'd have to drink quite a lot of it for there to be any effect. You can also only drink it if you're a low-risk pregnancy. If you've had a caesarean section before, we wouldn't recommend it, because of the very low risk of overstimulating the scar on your uterus," Marsh explains.

"With sex, there are prostaglandins in the sperm, which is the same hormone that's used to induce labour, so there's a little bit of evidence there but again it's not overwhelming," she adds.

It's also important not to have sex after your waters have broken, as this could increase the risk of infection.

Other methods like curry, pineapple, hot baths and acupuncture aren't supported by any evidence, but won't do you any harm if you want to try them. However, O'Brien warns against using castor oil, which has a laxative effect but doesn't help to induce labour.