Main Menu

Sections
About Natality Birth Parenting Newsflashes FAQs

Induction - Why?

The induction rate in the UK is creeping up and up – in some hospitals it is approaching 40%. Yet there is no evidence that this is helping to produce healthier mums or babies, in fact if you look at the rising caesarean, forceps and ventouse rates it may be doing quite the opposite. This article aims to help if you are faced with the suggestion of induction.

You might be offered induction for

...being overdue

...rupture of the membranes

...big baby

...a small baby

... medical reasons

Being “Overdue”

The most common reason for induction is because the baby is overdue or “post-term”. Doctors, and family and friends, often believe that being pregnant for more than 42 weeks or so increases the risk of your baby being stillborn or dying shortly after birth. This belief has recently been reinforced and shortened to between 41 and 42 weeks due to the influence of the government body NICE (National Institute for Clinical Excellence) and a research evidence review done in America by the Cochrane Library. However, there are some very respected obstetricians and midwives who argue that routine induction is not supported by the evidence. Some even argue that it is an unacceptable, illogical and dangerous interference in a normal situation.

How many women go past 40 weeks?

One UK study showed that 50% of all first time mothers have not had their babies by 40 weeks, that the average pregnancy length for a first time mother is 41 weeks and 1 day. Of those whose labour goes to 41 weeks, 60% will have gone into labour by 40 weeks plus 10 days.

“Say to yourself 3 times a day, after meals, the NORMAL gestation of a human baby is 37 to 42 weeks.”
-- Mary Cronk, independent midwife

Why is induction suggested?

The National Institute for Clinical Excellence (NICE) produced guidelines in 2001 which considered the risks of post-term pregnancy against induction and recommended to all obstetricians that induction any time after 41 weeks should be offered to all women and that it did not increase the risks of caesarean or other interventions nor increase the risk to mother or baby.

So what's the problem?

The evidence which the NICE panel considered when producing their guidelines was very similar to that reviewed by the Cochrane Library in the Cochrane Review of 1994, updated in 2006. These types of review are widely regarded as trustworthy or even labelled “Gold Top” by many medical professionals.

However, there are obstetricians and midwives who have very loudly condemned the Cochrane Review, most notably two obstetricians Metacongu and Hall, and it is worth reading their article “Nonsensus Consensus” for yourself if you can get hold of a copy – often libraries can help, the National Childbirth Trust has a research library for example and can get you a copy of such articles in return for a donation.

What's wrong with the evidence?

The Age of the Evidence

Some of the research trials which seemed to show an increased stillbirth in babies whose mothers awaited labour rather than being induced took place in the 1960's before the availability of most modern tests of baby wellbeing.

The risk is overstated

Of the 9 babies in the “wait for labour” part of the research who died, only two of them occurred in women who had received fetal testing and before 43 weeks and from possible length of pregnancy cause. As there was one death in the induction group the difference is not statistically significant and could be mere chance.

The authors say : “The higher risk that routine induction at 41 weeks aims to reduce is dubious, if it exists at all”.

It is increasingly difficult to find modern studies which compare large numbers of women with pregnancies going past 42 weeks because so many women are pressurised into accepting induction somewhere between 41 and 42 weeks. Perhaps, we simply do not know how many normal, healthy babies with mothers who do not have a medical problem and who have been having regular medical checks would be at risk from their pregnancy going to or over 42 weeks.

What we do know is that there is no evidence that the risk dramatically increases such that 15-20% of babies in the UK need to be induced at 41 weeks. Even if one accepts the figures given by NICE the risk is still very small. Metaconglu and Hall say, the “true risk in contrast to the perceived risk of a fetus dying between 41 weeks and 42 weeks in the absence of monitoring is only 0.1%” but do not define the “true risk” in monitored babies nor in babies over 42 weeks.

Rupture of the membranes

Received obstetric wisdom has it that if your waters break at 37 weeks plus then the sterile barrier between baby and the outside world has been broken and that your baby is at risk of infection. Induction is therefore suggested, in some hospitals this happens 12 hours after the waters broke. Yet even the notoriously conservative government body NICE (National Institute for Clinical Excellence) recommends waiting 96 hours (4 days) before inducing labour providing that both mum and baby are well. The research shows that 70% of women will go into labour within 24 houts and 96% will have gone into labour within 72 hours.

Remember that regardless of your local hospital policy it always remains your decision whether to be induced. The hospital would like you to be seen by a midwife to check that baby is engaged as there is an increased risk of cord prolapse if the waters have gone and baby's head is high. The hospital will also advise you to check your temperature at least once a day and to reconsider or go back in immediately for another check up if you feel unwell or you notice any change in the baby's movements.

Big Baby

There is no accurate way to tell how big a baby is in late pregnancy or to predict birth weight. Even if you consent to ultrasound examination, the measurements are not wholly accurate and can have such a large margin of error that the Royal College of Obstetricians and NICE have recommended that women shouldn't have their labours induced on the grounds of suspected fetal macrosomia (big baby). Yet there are still obstetricians who are doing this, even some who are performing caesarean for it.

We are all convinced that big babies mean big trouble for labouring women. Unhelpful family members, even midwives sometimes will eye up a woman's bump and make hissing noises similar to those used by car mechanics when asked how much the bill will be. It is worth repeating to yourself over and over again that no-one can tell from the size of your bump how big your baby will be.

Not only are most babies a perfectly ordinary size, most women have more than adequate internal pelvic dimensions for baby to be born. We'd have died out as a race if this wasn't the case. Yes babies are getting bigger but so are their mothers because we are healthier today than ever before -for example we don't have rickets which causes bone deformities and narrows the pelvis.

Better still, bigger babies aren't necessarily harder to birth. Despite what everyone thinks. What is important when giving birth is that the woman can be mobile and upright and thus capable of using the whole capacity of her pelvis to ease her baby out. She also need to be well supported and calm so that her body can release the hormones which make labour work. See How Birth Works.

So what happens when we tell a woman her baby is too big and then induce her? She may well be monitored throught labour, thus putting her into a position where she is lying on her back or semi reclining and therefore sitting on her own coccyx (tail-bone) which reduces her pelvic outlet by about 30%. She's not producing her own labour hormones, either because of induction drugs or because she's so terrified of birthing her baby, believing it to be of monster proportions. She may need epidural for her pain because her natural pain killing mechanisms have been obliterated by the induction drugs and by the adrenline she is releasing because she is so anxious. The epidural reduces her mobility still further and she has trouble birthing her baby who needs to be surgically extracted or gets shoulder dystocia. Her obstetrician will then tell her how lucky she was to be induced and how she has been saved by medical science when perhaps what has just happened was a self fulfilling prophecy, iatrogenesis.

But what if, we listened to NICE and let babies come when they were ready? What if we looked at the average head circumference of a 7lb baby and a 10lb baby and found that there was hardly any difference. What if we let a mother birth upright, confident in her body's ability to give birth?

Diabetes and gestational diabetes do produce bigger babies, NICE does still suggest induction is a good idea in this instance. As always this remains your decision. You might like to read the excellent resources on gestational diabetes: http://www.plus-size-pregnancy.org/gd/gd_index.html

Small Baby

Babies who are measured by ultrasound and found, over a period of time to be smaller than expected for their age are at risk of premature labour, of oxygen deprivation at birth and of potential brain damage after the birth. Truly slow or stalled growth is called Intrauterine Growth Restriction (IUGR)

Just measuring a baby once tells us little about how he is growing, if IUGR is suspected then measuring the baby over several weeks may give a better picture and enable a destinction to be made between a baby who is just small but still growing and a baby who is not growing well. However some parents have concerns about repeatedly exposing babies to ultrasound. Ultrasound does more than just measure size, it can also look at the amount of amniotic fluid, how well the blood is flowing through the umbilical cord and for any other potential causes of restricted growth. It is never wholly accurate but is believed to be better at accurately predicting small babies than large ones. As always any decision to induce can only be made with your informed consent.

Medical Reasons

There are some good reasons to be induced. It can be a lifesaving intervention for the mothers and babies that really need it. That's just probably not 40% of us! Conditions such as pre-eclampsia and obstetric choleastasis undoubtedly are good reasons for bring baby out early. However it is worth noting that many women in late pregnancy have a spike in their blood pressure just as they are about to go into labour. True pre-eclampsia has other signs and symptoms and it is worth having a proper discussion about the whole clinical picture and then deciding if you are happy that this is a good intervention for you and and your baby. See the pre-eclampsia article for more details of what to look for.

Does induction increase the risk of caesarean or other interventions?

The answer to this seems to be that it depends on which research you read and value. The Cochrane Review published in 2006 seems to show that women whose labours are induced after 41 weeks are not more likely to have epidurals, forceps, ventouse and caesarean.

If you are making this decision for yourself and your baby, it is worth considering the major criticisms of the Cochrane review which relate to caesarean rates.

Crossover

When the data was analysed it was done on an “intention to treat” basis not on what actually happened to the invidual women. So if a woman who was in the “wait for labour” group was induced, what happened to her and her baby was recorded and analysed as though she had gone into labour by herself. This seriously skews the analysis of risk to baby and risk of, for example, of caesarean.

The study that the Cochrane Review and others have used to back up their statement that induction doesn't increase caesarean rates is a large scale Canadian study done in the 1990's. Because of the “intention to treat” analysis what no-one did was looked at how many women who were actually induced versus those who waited for labour ended up with caesareans. Metaconglu and Hall have extrapolated from the data and they calculate that the rate more than doubles,

Not separating out First time mums from Second and subsequent mums.

This makes a difference because we know from other studies that inducing a second time mother has much less effect on her labour. As first time mothers more commonly go over 41 weeks of pregnancy anyway, this is a double whammy -more likely to be induced, more likely for induction to end in caesarean.

High Caesarean rates in both groups

This creates the illusion that inducing labour doesn't make a difference. The reason for the high rates, is probably that in the “waiting for labour” group there was a lot of monitoring going on and that in itself made both the women and their doctors very nervous and very inclined to go straight to caesarean if a problem appeared to occur.

“Over 99% of the supposedly compromised fetuses detected by monitoring most likely were not, but were rescued from normalcy by operative delivery for enhanced providor and patient anxiety.”

The Cascade of Intervention

The Cochrane review says that induction does not increase the numbers of women using epidural nor increase the numbers of babies needing to be born using forceps and ventouse . Although no-one has yet taken these figures apart, the suspicion is that , like the caesarean rate, both sides of the study were very high and because of the crossover effect they are not accurately comparing women who were induced with women who were not.

Certainly midwives and antenatal teachers and those who work with women, increasingly describe a system of intervention which goes something like this...

Induction ...leads to....more painful contractions...less mobility and electronic foetal monitoring...leads to...increased use of epidural....greater diagnosis of “fetal distress” ..leads to...forceps/ventouse and/or caesarean section.

All this matters because there is good evidence that surgical delivery of babies has effects on their long and short term health. It also matters to women, although crucially their opinions and feelings on how their babies were born was not even considered in either the Cochrane Review or NICE guidelines. Reaerch shows that if a woman has a traumatic birth experience she is more likely to suffer from postnatal depression and post traumatic stress disorder and more likely to choose not to have any more children.

So according to one pair of Obstetricians the advice women should be given about routine induction is...”that the higher risk is of caesarean delivery for dubious reasons and to avoid that they should labour and deliver where induction for dates alone is not the ritual at 41 weeks.”

What if I refuse induction?

Most hospitals in the UK have a policy of “offering” or recommending induction between 41 and 42 weeks. It is however, whatever their policy, your decision as to whether you

Accept induction on the date offered by the hospital.
Negotiate a later date, say at 42 plus 1 unless baby comes first.
Wait and see and then make a decision each day as to whether you want to wait any longer
Say no to induction and wait for labour to start.

If you go over 42 weeks your hospital should offer a scan to look at how much amniotic fluid is around the baby as a decrease in fluid is associated with problems for the baby and may be a good reason to induce. However, as always there may be disagreement about how accurate this measurement may be and in how the results are given to you.

Regular monitoring of the baby's heartbeat and assessment of mum's health are also considered to be a good idea and most hospitals will have a policy offering this. Again you are not obliged to follow the policy if you choose not to. It can be quite stressful to mothers to be asked to go into hospital for baby heart monitoring every 2 or 3 days and sometimes they are subjected to a lot of pressure from those doing the monitoring to reconsider a decision not to be induced. Again there may be a higher risk of the results being interpreted as the baby needing induction.

Some people argue that expectant management costs the NHS more money as the woman is being assessed frequently on an individual basis which may take up more consultant and midwifery time in the antenatal ward. Given the cost of longer hospital stays, increased caesarean and need for greater midwifery care in induced labours, this seems unlikely. There is however quite a compelling argument that truly high risk women and babies who do need medical care are being put at greater risk by the number of women on the labour ward having routine inductions and the increased load on already overstretched resources.