Induction for advanced maternal age

Is the recommendation of induction for advanced maternal age truly based on sound evidence? Or is it illogical when you break down and really look at the issues? What do older women need to know about the evidence in this area?

We hear from more and more women who are told that they need induction of labour because they are older. This issue also arose when the NICE guideline on induction of labour was revised in 2021. The recommendation to offer earlier induction to older women was not included in the final guideline. But we know it’s still being offered.

As I wrote when the guideline was published:

“One of the most controversial aspects of the draft [NICE] guideline was the proposed recommendation that earlier induction be offered to certain groups of women, including older women, larger women and women who conceived via IVF or ARTs.  It is clear that some groups of women/babies have a slightly higher chance of stillbirth compared to other groups. But data on this are often crude, the absolute risk may not be that high and we often have no trial evidence to show whether or not induction of labour would make a difference.” (Wickham 2021).

In this blog post, I’ll look at whether this recommendation is based on sound evidence and clear thinking.

 

Looking at the evidence

In fact, I’ve been looking at the research on induction of labour for advanced maternal age for several years now. I wrote a bit on this in Inducing labour: making informed decisions. I went into more depth on this topic in In Your Own Time.

After analysing the guidance and evidence on the topic of induction for advanced maternal age, my conclusion is that much of the guidance is not woman centred. It’s sometimes based on ageist and unfounded assumptions and there is a lack of evidence to support the idea that induction is beneficial for older women and their babies.

But there’s an important thing I’d like to say before I explain that.

Congratulations!

If you are a woman who is pregnant at an older-than-average age, then may I offer my sincere congratulations. We live in an ageist culture that doesn’t celebrate being pregnant at an older age nearly enough, so let me just briefly pause to say ‘yay’ and congratulations on your brilliant news. There are distinct advantages to having babies a few years later than average, just as there are different advantages to having babies when you’re younger. I hope the people around you are celebrating that, too. Please don’t let our ageist culture bring you down. Please celebrate yourself and your body and the advantages that come with a bit of age and wisdom.

The issue is that, if you’re pregnant and slightly older than average, you may well face a difficult decision somewhere around or just after your pregnancy reaches ‘term’. In fact these days, you don’t even need to be especially old to be offered induction for older maternal age. So please don’t think it’s you! The goalposts have moved. And it’s far less about you or the number of candles on your cake than it is about the obstetric model’s focus on intervention and care provider fear.

 

Is induction beneficial?

Induction of labour involves a series of procedures that artificially stimulate labour. I’ve discussed the pros and cons elsewhere, so I won’t repeat those here. Suffice to say that some women are really happy with their induction, but some are not.

Induction isn’t compulsory. You can always say no. You can always cancel an induction date that you’ve been given. You can always decide to await spontaneous labour.

But what does the evidence say? Are the things you might have heard or been told about risk at an older age really true?

One of the most fundamental questions is whether there is really an increased risk of losing a baby if you are older and, if so, whether induction can make a difference. It’s also important to consider the magnitude (size) of any risk so you can weigh that up against the risks of induction.

 

A tricky question

But these questions are harder to answer than you might think. Especially if you’ve talked with someone who is very keen on induction. Some people are only too happy to tell you that some studies show that waiting carries an increased chance of stillbirth for older women. Some will throw numbers at you which make it sound as if the risk is high.

But unfortunately that is not the whole story. There are a few good reasons to be concerned about the extent to which the findings of these studies are accurate and relevant to women making this decision today.

 

Separating risks

The first problem with the data that we have on induction for older maternal age is that older people tend to have more health problems (also called co-morbidities) than younger people. That’s just a fact of life. We don’t all have them, of course. It’s just more likely if you’re 35 than 20. And comorbidities can cause problems, too.

But many of the studies looking at the risk of stillbirth in older women haven’t tried to separate out any possible risk that comes from just being older and any possible risk that comes from having conditions such as high blood pressure.

Older women are also more likely than younger women to have conceived through the use of IVF (in vitro fertilisation) and other assisted reproductive technologies (ARTs). Many people try a baby for years before turning to medicine, so it’s inevitable that IVF/ART pregnancies are more likely in 37 year-olds than in 22 year-olds.

We also know that the use of IVF/ARTs increases the risk of some problems, including stillbirth. (Not that there is good evidence looking at whether induction is beneficial in this situation either, but that’s another question.) Both the use of ARTs and the existence of other problems (sometimes called co-morbidity) can lead to problems in themselves. So a good research study which looks at whether induction for older maternal age needs to take that into account.

In simple terms, researchers should try to separate out the risk caused by these known problems from any risk caused simply by age.

The problem? Most of the researchers who have looked at this area haven’t done that. Which means that their findings aren’t that helpful to the majority of people making decisions about induction.

 

Studies that do control

The scientific opinion paper that the RCOG (2013) published on this topic acknowledged this problem. They cited two papers that controlled for (took into account) these factors.

The first was by Fretts et al (1995), who used data gathered in Canada from 1961 to 1993. And Pasupathy et al (2011) analysed data gathered from the experiences of Scottish women who gave birth between 1985 and 2004.

Unfortunately, both of these studies included women who gave birth so long ago that it is questionable whether their experiences can be compared to those of women giving birth today (Mander 2013, Wickham 2021).

Like so many studies, almost all of the participants were white Europeans as well.

This really calls the data into question. I’m updating this blog post in 2022. The women in these studies gave birth between two and six decades ago and some will be (or would have been) a hundred years old now. The world, women’s health and the maternity services have changed a huge amount in that time. All women in high-income countries are now offered tests and technologies that were not available to the women in those studies. It’s possible that some of the problems they experienced wouldn’t even be an issue today. Today, some of the things the women/babies with problems experienced might have been spotted and sorted well before induction was even put on the table.

 

The myth of poor uterine function

My colleague Rosemary Mander pointed out another significant issue with the RCOG (2013) paper on older maternal age.

‘There are also a number of unexplained slightly paradoxical points which reduce the reader’s confidence in the paper, such as the statement ‘that ageing impairs myometrial [uterus muscle] function’ (2013). This leads the reader to question why, if this is so, are such ‘older mothers’ being recommended to labour at all?’ (Mander 2013: 48)

Quite.

But before anyone wonders whether ‘the better answer’ is cesarean section, let’s look at the basis of the RCOG’s original statement. Because this is just one of a number of statements that have been made over many years about the inferiority of certain types of bodies. Sometimes it’s female bodies, sometimes it’s older bodies, larger bodies or Black or Brown bodies. People who fall into one of those groups have a hard enough time. For those who fit more than one, it’s even worse.

But these prejudices are generally not evidence-based. They reflect bias and racist, sexist and ageist attitudes.

Let’s take the claim that aging impairs myometrial muscle to the extent that older women can’t labour well, for instance. I haven’t seen good evidence that this statement is true. Yes, it’s discussed ‘in the scientific literature,’ but so are unicorns and yeti. That doesn’t mean we have evidence of their existence. We do, however, have plenty of evidence that labour progress can be negatively affected by interference with normal female physiology.

If people are truly concerned about this, they should thoroughly investigate any such concern. Especially given its potential impact. However, to my knowledge, this research has not been done. Assumptions have been made. And the problem with assumptions is that they can affect the beliefs of care providers and others. This can sometimes mean that beliefs turn into self-fulfilling prophecies.

 

The lack of logic

The second problem with the assumptions made on this topic runs along similar lines.

Remember that some of these studies found that women over 40 were slightly more likely to have a stillborn baby?

(And yes, by the way, you read that correctly. It was women over 40. Please don’t ask me why it is that induction for older maternal age is now often offered to women younger than that. I don’t have a good answer other than to point out that many recommendations aren’t based on good evidence.) 

Pasupathy et al (2011) concluded that the increase that they found in stillbirths in women over 40 was the result of hypoxia. Hypoxia means a lack of oxygen to the brain. But if their theory is correct (and we don’t know for sure either way), then how is induction of labour an appropriate response? Induction of labour generally involves giving exogenous oxytocin by a drip, and one of the many downsides of using exogenous oxytocin is that it can cause hypoxia.

Like so many things in obstetrics, it’s just not logical when you start to analyse it.

 

Assessing risk

There’s one more really important point that I want to raise when it comes to considering induction of labour in older women. 

I’ve pointed out that the studies suggesting that there’s a raised risk are older and that the risk might not be the same today. But, even if older women do have an increased risk of stillbirth, we don’t know if induction of labour reduces that risk.

That’s because we can’t know if an intervention such as induction is effective unless we carry out sufficiently robust randomised controlled trials.

To date, I know of no such trial.

We just don’t have good evidence to suggest that induction of labour is beneficial for older women.

 

Where do we go from here?

As in so many areas, there is a significant problem here. Older women are facing an enormous decision and coming under pressure to accept induction of labour before their baby and body can go into labour for itself. And yet there is a lack of good data to which they can refer and use as a basis for their decision.

Rather than routinely offering justifications for induction which sometimes seem to be based more on fear than evidence, how about if we routinely offered a bit of clear thinking? It would be great if there was more honesty about what we can and can not tell from the research. And an enormous dollop of support and TLC for those women who have to make such decisions?

And (with many thanks to Rosemary for highlighting this too) a few more ‘yay’s in celebration of their good news might not go amiss either…

 

If you’d like to know a bit more about the (lack of) evidence for induction for older women, and a lot more about the wider picture around induction of labour, you might enjoy my latest book. It’s called In Your Own Time: how western medicine controls the start of labour and why this needs to stop.

If you’d like to read more about the process of induction of labour, for older women and in other circumstances, you might enjoy my book, Inducing labour: making informed decisions.

 

References

Fretts RC, Schmittdiel J, McLean FH et al (1995). Increased maternal age and the risk of fetal death.  NEJM 333:953–57.

Mander R (2013). Induction of labour for advancing maternal age. EM 4(8): 46-49.

Pasupathy D, Wood AM, Pell JP et al (2011).  Advanced maternal age and the risk of perinatal death due to intrapartum anoxia at term. JECH 65:241–45.

Royal College of Obstetricians and Gynaecologists (2013).  Induction of labour at term in older mothers (Scientific Impact Paper No. 34).  London: RCOG.

Wickham (2021). In Your Own Time: how western medicine controls the start of labour and why this needs to stop. Avebury: Birthmoon Creations.

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